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  <front>
    <journal-meta>
      <journal-id journal-id-type="nlm-ta">Arq Bras Cardiol</journal-id>
      <journal-id journal-id-type="publisher-id">abc</journal-id>
      <journal-title-group>
        <journal-title>Arquivos Brasileiros de Cardiologia</journal-title>
        <abbrev-journal-title abbrev-type="publisher">Arq. Bras. Cardiol.</abbrev-journal-title>
      </journal-title-group>
      <issn pub-type="ppub">0066-782X</issn>
      <issn pub-type="epub">1678-4170</issn>
      <publisher>
        <publisher-name>Sociedade Brasileira de Cardiologia - SBC</publisher-name>
      </publisher>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="publisher-id" specific-use="scielo-v3">Hmhzjvnr4CFxFcdbjnbhxCg</article-id>
      <article-id pub-id-type="publisher-id" specific-use="scielo-v2">S0066-782X2016004100116</article-id>
      <article-id pub-id-type="publisher-id" specific-use="previous-pid">S0066-782X2016005018102</article-id>
      <article-id pub-id-type="doi">10.5935/abc.20160096</article-id>
      <article-categories>
        <subj-group subj-group-type="heading">
          <subject>Original Article</subject>
        </subj-group>
      </article-categories>
      <title-group>
        <article-title>Low Prevalance of Major Events Adverse to Exercise Stress Echocardiography</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <name>
            <surname>Andrade</surname>
            <given-names>Stephanie Macedo</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Telino</surname>
            <given-names>Caio Jos&#233; Coutinho Leal</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Sousa</surname>
            <given-names>Ant&#244;nio Carlos Sobral</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Melo</surname>
            <given-names>Enaldo Vieira de</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Teixeira</surname>
            <given-names>Carla Carolina Cardoso</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Teixeira</surname>
            <given-names>Clarissa Karine Cardoso</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Santana</surname>
            <given-names>Jaquiele Santos</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Mota</surname>
            <given-names>Igor Larchert</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Matos</surname>
            <given-names>Carlos Jos&#233; Oliveira de</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Oliveira</surname>
            <given-names>Joselina Luzia Menezes</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
          <xref ref-type="corresp" rid="c1"/>
        </contrib>
      </contrib-group>
      <aff id="aff1">
        <label>1</label>
        <institution content-type="orgname">Universidade Federal de Sergipe</institution>
        <addr-line>
          <named-content content-type="city">Aracaju</named-content>
          <named-content content-type="state">SE</named-content>
        </addr-line>
        <country country="BR">Brazil</country>
        <institution content-type="original">Universidade Federal de Sergipe, Aracaju, SE- Brazil</institution>
        <institution content-type="normalized">Universidade Federal de Sergipe</institution>
      </aff>
      <aff id="aff2">
        <label>2</label>
        <institution content-type="orgname">Hospital e Funda&#231;&#227;o S&#227;o Lucas</institution>
        <institution content-type="orgdiv1">Centro de Ensino e Pesquisa</institution>
        <institution content-type="orgdiv2">Laborat&#243;rio de Ecocardiografia</institution>
        <addr-line>
          <named-content content-type="city">Aracaju</named-content>
          <named-content content-type="state">SE</named-content>
        </addr-line>
        <country country="BR">Brazil</country>
        <institution content-type="original">Centro de Ensino e Pesquisa e Laborat&#243;rio de Ecocardiografia (ECOLAB) do Hospital e Funda&#231;&#227;o S&#227;o Lucas, Aracaju, SE - Brazil</institution>
      </aff>
      <author-notes>
        <corresp id="c1"><bold>Mailing Address: Joselina Luzia Menezes Oliveira</bold>. Pra&#231;a Graccho Cardoso, 76/402, S&#227;o Jos&#233;. Postal Code 49015-180, Aracaju, SE - Brazil E-mail: <email>jlobelem@cardiol.br</email>, <email>joselinamenezes@gmail.com</email>
				</corresp>
        <fn fn-type="con">
          <p>
            <bold>Author contributions</bold>
          </p>
          <p>Conception and design of the research:Andrade SM, Sousa ACS, Melo EV, Teixeira CCC, Teixeira CKC, Santana JS, Mota IL, Matos CJO, Oliveira JLM. Acquisition of data: Andrade SM, Telino CJCL, Teixeira CCC, Teixeira CKC, Santana JS, Mota IL, Matos CJO, Oliveira JLM. Analysis and interpretation of the data: Andrade SM, Sousa ACS, Melo EV, Oliveira JLM. Statistical analysis: Melo EV, Matos CJO, Oliveira JLM. Writing of the manuscript: Andrade SM, Telino CJCL, Sousa ACS. Critical revision of the manuscript for intellectual content: Andrade SM, Sousa ACS, Matos CJO, Oliveira JLM. Supervision / as the major investigador: Andrade SM, Oliveira JLM.</p>
        </fn>
        <fn fn-type="conflict">
          <p>
            <bold>Potential Conflict of Interest</bold>
          </p>
          <p>No potential conflict of interest relevant to this article was reported.</p>
        </fn>
      </author-notes>
      <pub-date pub-type="epub">
        <day>27</day>
        <month>06</month>
        <year>2016</year>
      </pub-date>
      <pub-date pub-type="collection">
        <month>08</month>
        <year>2016</year>
      </pub-date>
      <volume>107</volume>
      <issue>2</issue>
      <fpage>116</fpage>
      <lpage>123</lpage>
      <history>
        <date date-type="received">
          <day>07</day>
          <month>05</month>
          <year>2015</year>
        </date>
        <date date-type="rev-recd">
          <day>18</day>
          <month>03</month>
          <year>2016</year>
        </date>
        <date date-type="accepted">
          <day>24</day>
          <month>03</month>
          <year>2016</year>
        </date>
      </history>
      <permissions>
        <license license-type="open-access" xlink:href="http://creativecommons.org/licenses/by/4.0/" xml:lang="en">
          <license-p>This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.</license-p>
        </license>
      </permissions>
      <abstract>
        <title>Abstract</title>
        <sec>
          <title>Background:</title>
          <p>Stress echocardiography is well validated for diagnosis and risk stratification of coronary artery disease. Exercise stress echocardiography (ESE) has been shown to be the most physiological among the modalities of stress, but its safety is not well established.</p>
        </sec>
        <sec>
          <title>Objective:</title>
          <p>To study the complications related to ESE and clinical and echocardiographic variables most commonly associated with their occurrence.</p>
        </sec>
        <sec>
          <title>Methods:</title>
          <p>Cross-sectional study consisting of 10250 patients submitted to ESE for convenience, from January 2000 to June 2014. Cardiac Arrhythmias (CA) were the most frequent complications observed during the examination. The volunteers were divided into two groups according to the occurrence of CA during ESE: G1 group, composed of patients who have CA, and G2 formed by individuals who did not show such complication. Results: Group G1, consisting of 2843 patients (27.7%), and Group G2 consisting of 7407 patients (72.3%). There was no death, acute myocardial infarction, ventricular fibrillation or asystole. Predominant CAs were: supraventricular extrasystoles (13.7%), and ventricular extrasystoles (11.5%). G1 group had a higher mean age, higher frequency of hypertension and smoking, larger aortic roots and left atrium (LA) and lower ejection fraction than G2. G1 group also had more ischemic changes (p &lt; 0.001). The predictor variables were age (RR 1.04; [CI] 95% from 1.038 to 1.049) and LA (RR 1.64; [CI] 95% from 1.448 to 1.872).</p>
        </sec>
        <sec>
          <title>Conclusion:</title>
          <p>ESE proved to be a safe modality of stress, with non-fatal complications only. Advanced age and enlargement of the left atrium are predictive of cardiac arrhythmias.</p>
        </sec>
      </abstract>
      <kwd-group xml:lang="en">
        <title>Keywords:</title>
        <kwd>Coronary Artery Disease</kwd>
        <kwd>Exercise / physiology</kwd>
        <kwd>Exercise Test</kwd>
        <kwd>Safety</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec sec-type="intro">
      <title>Introduction</title>
      <p>Coronary artery disease (CAD) is the leading cause of morbidity and mortality in the world.<xref ref-type="bibr" rid="B1">1</xref><sup>,</sup><xref ref-type="bibr" rid="B2">2</xref> In Brazil, cardiovascular diseases (CVD) are responsible for one third of deaths annually.<xref ref-type="bibr" rid="B3">3</xref> Due to a large social impact, early examination of CAD has become mandatory to identify not only a high-risk group, in which additional interventions are necessary, but also to select a low-risk subgroup, in which additional procedures would not be required.<xref ref-type="bibr" rid="B4">4</xref><sup>,</sup><xref ref-type="bibr" rid="B5">5</xref>
			</p>
      <p>Ergometric test (ET) is the non-invasive examination initially recommended for the diagnosis and stratification of risk in patients with suspected CAD.<xref ref-type="bibr" rid="B6">6</xref><sup>-</sup><xref ref-type="bibr" rid="B8">8</xref> However, this method has limitations in certain situations, such as left bundle branch block or ST segment changes in resting electrocardiogram (ECG).<xref ref-type="bibr" rid="B8">8</xref> Futhermore, changes in wall motion of the left ventricle detected through stress echocardiography (SE) appear earlier in the ischemic cascade than angina or ST segment changes, which gives SE better sensitivity and specificity.<xref ref-type="bibr" rid="B9">9</xref><sup>-</sup><xref ref-type="bibr" rid="B12">12</xref>
			</p>
      <p>SE, which was introduced in the late 70's, initially as pharmacological stress testing, is the most well validated method for the diagnosis and stratification od risk, prognosis, and evaluation of myocardial viability in patients with CAD.<xref ref-type="bibr" rid="B13">13</xref><sup>-</sup><xref ref-type="bibr" rid="B18">18</xref> Even though the use of drugs such stressors has proven safe, recent literature has firmly focused on its complications.<xref ref-type="bibr" rid="B19">19</xref><sup>-</sup><xref ref-type="bibr" rid="B29">29</xref>
			</p>
      <p>Although both methods of testing yield similarly accurate results in patients with well-preserved physical capacity, Exercise stress echocardiography (ESE) is the better choice over pharmacological stress testing, with the latter being reserved to physically impaired individuals or those with low motivation to exercise.<xref ref-type="bibr" rid="B30">30</xref><sup>,</sup><xref ref-type="bibr" rid="B31">31</xref> ESE is also a physiological and versatile method, whose use has been growing. However, literature on the method's safety and its complications is scarce.<xref ref-type="bibr" rid="B32">32</xref><sup>,</sup><xref ref-type="bibr" rid="B33">33</xref> Therefore, the objective of this study is to analyse the complications related to ESE and the clinical and echocardiographical variables that are predictors of these events.</p>
    </sec>
    <sec sec-type="methods">
      <title>Methods</title>
      <p>This is an analytical and descriptive cross-sectional study conducted between January 2000 and June 2014</p>
      <sec>
        <title>Patients</title>
        <p>The convenience sample was made up of 10250 patients with suspected or established CAD who were submitted to stress echocardiography through physical effort at the Echocardiography Laboratory of the <italic>Cl&#237;nica e Hospital S&#227;o Lucas (ECOLAB)</italic> in Aracaju, state of S&#227;o Paulo. All patients over 25 years old, referred to the service by assisting doctors, were included, with the exception of those who refused to participate in the study. The recommendations for the exam were: pre-operative, typical or atypical chest pain, risk stratification, positive or negative ET, inefficient ET, check-up.</p>
        <p>Patients were divided into two groups according to the occurrence of the most frequent complications observed in ESE: G1 group - patients who presented such complications in the exam, and G2 group - individuals with no complications.</p>
      </sec>
      <sec>
        <title>Clinical characteristics</title>
        <p>Clinical data were collected and recorded through interviews conducted prior to the procedure. A structure questionnaire investigating weight, height, symptons such as dyspnea and chest pain, medications, CAD risk factors and history of personal or family heart disease was used, together with relevant data such as previous CADs such as acute myocardial infarction, percutaneous and surgical revascularization. In addition, previous results from lab work and examinations of the cardiovascular system were registered.</p>
        <p>Obesity was characterized when body mass surpassed 30 kg/m<sup>2</sup>. Hypercholesterolemia was defined as total serum cholesterol levels of over 200 mg/dL (after fasting for 12 hours), and hypertriglyceridemia as serum triglycerides levels greater than 150 mg/dL (after fasting for 12 hours) or use of antilip&#234;mico agent (statins and / or fibrates).</p>
        <p>Systemic arterial hypertension was considered when blood pressure levels measured in the arm, in resting condition, were systolic blood pressure &#8805; 140 mmHg and/or diastolic &#8805; 90 mmHg, or when there was use of antihypertensive medication.</p>
        <p>Diabetes mellitus was defined by the presence of fasting glucose over 126 mg/dL or by the use of insulin or oral hypoglycemic agents.</p>
        <p>Old myocardial infarction was defined through clinical history and/or previous supplementary exams, such as ECG, echocardiogram and/or coronary angiography.</p>
      </sec>
      <sec>
        <title>Ergometric Test</title>
        <p>Firstly, the protocol consisted of the 12-lead ECG and resting echocardiogram after clinical investigation. After that, physical effort on treadmill was performed, and soon after echocardiographic images were acquired again.</p>
        <p>All patients were submitted to the standard Bruce or Ellestad protocols protocols during ergometric tests. There was continuous monitoring of heart rate, and the patients were encouraged to reach their maximum physical effort. For metabolic calculations, the volume of inspired oxygen at peak exercise (VO<sub>2</sub>max) was obtained indirectly through the following formula: VO<sub>2</sub>max = 14.76 - 1.379t + 0.451t<sup>2</sup> - 0.012t<sup>3</sup>, in which t is the duration of the test<xref ref-type="bibr" rid="B34">34</xref> in minutes. The load was expressed as metabolic equivalents, in which 1 MET corresponds to 3.5 mL/kg&#183;min of inspired VO<sub>2</sub>, in resting.<xref ref-type="bibr" rid="B35">35</xref> Throughout the test, the individuals were continuously monitored by 3-lead ECG.</p>
        <p>Ischemic electrocardiographic changes were designated to the occurrence of descending or horizontal ST segment depression &#8805; 1 mm for men and &#8805; 1,5 mm for women at 0.08 seconds from the J point.<xref ref-type="bibr" rid="B8">8</xref>
				</p>
      </sec>
      <sec>
        <title>Exercise Stress Echocardiography</title>
        <p>The environment for the performance of the exam is ergonomically projected by a constantly trained team, due to the hospital reputation as a reference hospital in the cardiology department and its level 3 accreditation by specific assessment. As a routine procedure, the suspension of beta-blockers three days before the exam is recommended, while other drugs are kept in use.</p>
        <p>Exams were carried out with Hewlett Packard/Phillips SONOS 5500 up to 2012 and then with Phillips IE-33, with due observance of technical aspects described by Schiller et al.<xref ref-type="bibr" rid="B36">36</xref> Bidimensional echocardiographic images were obtained at the parasternal and apical acoustic windows during resting and immediately after effort, with the patient in the left lateral decubitus and simultaneous electrocardiographic recording. The wall motion of the left ventricular (LV) wall was evaluated by experienced echocardiographer, with level III, as required by the American Echocardiography Society. Segmental wall thickening of the LV was quantitatively evaluated in resting and after physical effort through the 16 segment model with the following gradual rank: 1, normal; 2, hypokinetic; 3, akinetic; 4, dyskinetic. The left ventricular motion score index (LVMSI) was calculated in resting and during physical exercise as the sum of the scores given to each of the 16 segments divided by the number of segments evaluated at that moment. LVMSI of 1 corresponds to normality; from 1.1 to 1.6 corresponds to mild dysfunction; from 1.61 to 2, moderate dysfunction. Values of over 2 represent severe dysfunction.<xref ref-type="bibr" rid="B36">36</xref> The difference between resting and physical exercise LVMSIs is called &#916;LVMSI. The development of a new change in the parietal motility or worsening of existing dyssynergy (&#916;LVMSI &#8800; 0) were considered indicative of myocardial ischemia.</p>
      </sec>
      <sec>
        <title>Analysis of complication occurrence</title>
        <p>Patients were monitored for possible complications by 12-lead ECG before, during and after physical exercise stress. The researched complications and their respective definitions were based on those described by Geleijnse et al.<xref ref-type="bibr" rid="B29">29</xref>
				</p>
        <p>Major complications considered were: death, acute myocardial infarction, cardiac rupture, ventricular fibrillation and cardiac asystole.</p>
        <p>Minor complications were defined as: atrioventricular block (AVB), coronary spasm, stroke, hypotension and hypertension at peak exercise, sustained ventricular tachycardia (&gt; 30 beats / min), non-sustained ventricular tachycardia, sustained supraventricular tachycardia, non-sustained supraventricular tachycardia, ventricular premature beats and supraventricular extrasystoles.</p>
      </sec>
      <sec>
        <title>Statistical Analysis</title>
        <p>Categorical variables were presented as percentages and analyzed using the chi-square test (c<sup>2</sup>) or Fisher's exact test. Continuous variables were represented by mean +/- standard deviation and compared with the aid of Student's unpaired t test or Mann-Whitney U test, as appropriate.</p>
        <p>To assess the risk factors predictive of complications to ESE we used univariate and multivariate Cox regression analysis. The variables included in the multivariate model were all of those with p &lt; 0.1 in the univariate analysis. Multicollinearity problems were resolved prior to insertion of the variables in the model. Forward selection of variables was used. Variables that remained in the model were tested for possible interactions. Proportional hazards assumption was tested by Schoenfeld residual testing for each of the variables that remained in the final model. Values of p &lt; 0.05 were considered significant. Statistical analysis were processed by the software <italic>Statistical Package for the Social Sciences</italic> (<italic>SPSS</italic>) 21.0 (Chicago, IL).</p>
      </sec>
      <sec>
        <title>Ethical aspects</title>
        <p>The ethical principles for human experimentation were followed thoroughly, and all patients signed an informed consent. The study was approved by the Ethics Committee of the Federal University of Sergipe (CAAE 1818.0.000.107-06).</p>
      </sec>
    </sec>
    <sec sec-type="results">
      <title>Results</title>
      <p>A total of 10250 patients participated in the study; 4936 males (48.2%), with a mean age of 57.19 &#177; 11.24 years, limited to 25 and 93 years of age. There was no record of major complications such as death, acute myocardial infarction, cardiac rupture, ventricular fibrillation and cardiac asystole.</p>
      <p>Cardiac arrhythmias were the most frequent observed complication during the exam, and thus the distribution of the groups was as follows: 2843 patients in the G1 group (27.7%), and 7407 patients in the G2 group (72.3%).</p>
      <p>One case of each of the following complications was recorded: AVB; coronary spasm; stroke; and arterial hypotension, which represented 0.009% of the sample. Arterial hypertension at the peak of physical effort was observed in 1011 individuals (9.9% of the population), of which 82% presented with systemic arterial hypertension (SAH) before the exam.</p>
      <p>The most frequently observed complications in this study were cardiac arrhythmias. The observed rates were non-sustained ventricular and supraventricular tachycardia and ventricular and supraventricular extrasystoles be it isolated, in saves, bigeminal, monomorphic or polymorphic. Their frequency is described in <xref ref-type="table" rid="t1">Table 1</xref>. In all cases they were reversed with the cessation of physical effort and use of isosorbide dinitrate and inhaled oxygen when in the presence of associated myocardial ischemia, with no hemodynamic repercussions that would require ICU admission, considering that ventricular fibrillation or sustained ventricular tachycardia were not recorded.</p>
      <table-wrap id="t1">
        <label>Table 1</label>
        <caption>
          <title>Frequency of cardiac arrhythmias during ESE</title>
        </caption>
        <table frame="hsides" rules="groups">
          <colgroup width="50%">
            <col/>
            <col/>
          </colgroup>
          <thead>
            <tr>
              <th align="left">Cardiac Arrhythmia</th>
              <th align="center">Frequency<break/>n = 10250</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td align="left">Sustained ventricular tachycardia</td>
              <td align="center">0 (0%)</td>
            </tr>
            <tr>
              <td align="left">Non-sustained ventricular tachycardia</td>
              <td align="center">114 (1.1%)</td>
            </tr>
            <tr>
              <td align="left">Sustained supraventricular tachycardia</td>
              <td align="center">0 (0%)</td>
            </tr>
            <tr>
              <td align="left">Non-sustained supraventricular tachycardia</td>
              <td align="center">645 (6.2%)</td>
            </tr>
            <tr>
              <td align="left">Ventricular extrasystoles</td>
              <td align="center">1186 (11.5%)</td>
            </tr>
            <tr>
              <td align="left">Supraventricular extrasystoles</td>
              <td align="center">1418 (13.7%)</td>
            </tr>
          </tbody>
        </table>
        <table-wrap-foot>
          <fn id="TFN01">
            <p>ESE: exercise stress echocardiography</p>
          </fn>
        </table-wrap-foot>
      </table-wrap>
      <p>The 10250 patients were divided into two groups: G1 group - made up of 2843 patients (27.7%) that presented with cardiac arrhythmias during the exam, and G2 group - made up of 7404 patients (72.3%) with no arrhythmias.</p>
      <sec>
        <title>Clinical characteristics of the groups</title>
        <p>G1 group presented higher mean age, higher SAH frequency and smoking. With regoards to gender and other associated comorbidities, both groups presented similar frequencies (<xref ref-type="table" rid="t2">Table 2</xref>)</p>
        <table-wrap id="t2">
          <label>Tabela 2</label>
          <caption>
            <title>Clinical characteristics of patients with (G1) or without (G2) cardiac arrhythmias during ESE</title>
          </caption>
          <table frame="hsides" rules="groups">
            <colgroup width="25%">
              <col/>
              <col/>
              <col/>
              <col/>
            </colgroup>
            <thead>
              <tr>
                <th align="left">Clinical characteristics</th>
                <th align="center">G1<break/>n = 2843 (27.7%)</th>
                <th align="center">G2<break/>n = 7407 (72.2%)</th>
                <th align="center">p</th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td align="left">Male</td>
                <td align="center">1410 (49.6%)</td>
                <td align="center">3525 (47.6%)</td>
                <td align="center">0.06</td>
              </tr>
              <tr>
                <td align="left">Age (mean in years)</td>
                <td align="center">60.81 &#177; 10.78</td>
                <td align="center">55.79 &#177; 11.1</td>
                <td align="center">&lt; 0.001</td>
              </tr>
              <tr>
                <td align="left">BMI (kg/m<sup>2</sup>)</td>
                <td align="center">27.2 &#177; 4.28</td>
                <td align="center">27.3 &#177; 4.43</td>
                <td align="center">0.3</td>
              </tr>
              <tr>
                <td align="left">SAH</td>
                <td align="center">1828 (64.3%)</td>
                <td align="center">4251 (57.4%)</td>
                <td align="center">&lt; 0.001</td>
              </tr>
              <tr>
                <td align="left">Diabetes Mellitus</td>
                <td align="center">102 (3.6%)</td>
                <td align="center">637 (8.6%)</td>
                <td align="center">0.12</td>
              </tr>
              <tr>
                <td align="left">Dyslipidemia</td>
                <td align="center">1709 (60.1%)</td>
                <td align="center">4370 (59%)</td>
                <td align="center">0.33</td>
              </tr>
              <tr>
                <td align="left">Smoking</td>
                <td align="center">114 (4%)</td>
                <td align="center">378 (5.1%)</td>
                <td align="center">0.02</td>
              </tr>
              <tr>
                <td align="left">Family history of heart disease</td>
                <td align="center">1595 (56.1%)</td>
                <td align="center">4163 (56.2%)</td>
                <td align="center">0.92</td>
              </tr>
              <tr>
                <td align="left">Dyspnea</td>
                <td align="center">264 (9.3%)</td>
                <td align="center">555 (7.5%)</td>
                <td align="center">0.003</td>
              </tr>
              <tr>
                <td align="left">Precordialgia</td>
                <td align="center">816 (28.7%)</td>
                <td align="center">2326 (31.4%)</td>
                <td align="center">0.191</td>
              </tr>
              <tr>
                <td align="left">Previous AMI</td>
                <td align="center">165 (5.8%)</td>
                <td align="center">318 (4.3%)</td>
                <td align="center">0.002</td>
              </tr>
              <tr>
                <td align="left">Angioplasty</td>
                <td align="center">213 (7.5%)</td>
                <td align="center">533 (7.2%)</td>
                <td align="center">0.639</td>
              </tr>
              <tr>
                <td align="left">Myocardial revascularization</td>
                <td align="center">205 (7.2%)</td>
                <td align="center">385 (5.2%)</td>
                <td align="center">&lt; 0.001</td>
              </tr>
              <tr>
                <td align="left">Beta-blocker</td>
                <td align="center">690 (24.3%)</td>
                <td align="center">1555 (21.0%)</td>
                <td align="center">&lt; 0.001</td>
              </tr>
              <tr>
                <td align="left">Calcium channel blockers</td>
                <td align="center">239 (8.4%)</td>
                <td align="center">481 (6.5%)</td>
                <td align="center">0.001</td>
              </tr>
              <tr>
                <td align="left">IACE</td>
                <td align="center">318 (11.2%)</td>
                <td align="center">674 (9.1%)</td>
                <td align="center">0.001</td>
              </tr>
              <tr>
                <td align="left">ARB</td>
                <td align="center">424 (14.9%)</td>
                <td align="center">1059 (14.3%)</td>
                <td align="center">0.468</td>
              </tr>
              <tr>
                <td align="left">Statin</td>
                <td align="center">640 (22.5%)</td>
                <td align="center">1504 (20.3%)</td>
                <td align="center">0.016</td>
              </tr>
              <tr>
                <td align="left">Glycemia</td>
                <td align="center">100.03 &#177; 25.26</td>
                <td align="center">99.72 &#177; 29.23</td>
                <td align="center">0.907</td>
              </tr>
              <tr>
                <td align="left">Total cholesterol (mg/dL)</td>
                <td align="center">196.86 &#177; 47.81</td>
                <td align="center">192.88 &#177; 46.28</td>
                <td align="center">0.364</td>
              </tr>
              <tr>
                <td align="left">HDL (mg/dL)</td>
                <td align="center">49.95 &#177; 13.97</td>
                <td align="center">46.54 &#177; 13.33</td>
                <td align="center">0.748</td>
              </tr>
              <tr>
                <td align="left">LDL (mg/dL)</td>
                <td align="center">123.28 &#177; 42.16</td>
                <td align="center">116.87 &#177; 41.28</td>
                <td align="center">0.115</td>
              </tr>
              <tr>
                <td align="left">Triglycerides (mg/dL)</td>
                <td align="center">148.95 &#177; 89.06</td>
                <td align="center">154.78 &#177; 100.74</td>
                <td align="center">0.535</td>
              </tr>
            </tbody>
          </table>
          <table-wrap-foot>
            <fn id="TFN02">
              <p>BMI: body mass index; SAH: systemic arterial hypertension; AMI: acute myocardial infarction; IACE: inhibitor of angiotensin converting enzyme; ARB: angiotensin receptor blocker; HDL: hight density lipoproteins, LDL: low density lipoproteins.</p>
            </fn>
          </table-wrap-foot>
        </table-wrap>
      </sec>
      <sec>
        <title>Echocardiographic characteristics of the groups</title>
        <p>In the transthoracic Doppler echocardiography there was significant difference in the diameters of the aorta and the left atrium and in the left ventricular mass and thickness. Ejection fraction of the LV was preserved in both groups, which was lower in G1 patients (<xref ref-type="table" rid="t3">Table 3</xref>).</p>
        <table-wrap id="t3">
          <label>Table 3</label>
          <caption>
            <title>Echocardiographic characteristis of patients with (G1) or without (G2) cardiac arrhythmia during ESE</title>
          </caption>
          <table frame="hsides" rules="groups">
            <colgroup>
              <col width="1%"/>
              <col width="24%"/>
              <col width="24%"/>
              <col width="24%"/>
              <col width="24%"/>
            </colgroup>
            <thead>
              <tr>
                <th align="left" colspan="2">Echocardiographic characteristis</th>
                <th align="center">G1<break/>n = 2843 (27,7%)</th>
                <th align="center">G2<break/>n = 7407 (72,3%)</th>
                <th align="center">p</th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td align="left" colspan="2">Aorta (cm)</td>
                <td align="center">3.23 &#177; 0.39</td>
                <td align="center">3.17 &#177; 0.4</td>
                <td align="center">&lt; 0.001</td>
              </tr>
              <tr>
                <td align="left" colspan="2">LA (cm)</td>
                <td align="center">3.87 &#177; 0.47</td>
                <td align="center">3.76 &#177; 0.43</td>
                <td align="center">&lt; 0.001</td>
              </tr>
              <tr>
                <td align="left" colspan="2">LA volume (ml/m<sup>2</sup>)</td>
                <td align="center">24.26 &#177; 24.25</td>
                <td align="center">22.52 &#177; 26.02</td>
                <td align="center">0.11</td>
              </tr>
              <tr>
                <td align="left" colspan="2">E/e&#180; ratio</td>
                <td align="center">9.94 &#177; 3.4</td>
                <td align="center">9.41 &#177; 3.36</td>
                <td align="center">0.005</td>
              </tr>
              <tr>
                <td align="left" colspan="2">LV mass index (g/m<sup>2</sup>)</td>
                <td align="center">95.2 &#177; 87.74</td>
                <td align="center">97.9 &#177; 62.88</td>
                <td align="center">&lt; 0.001</td>
              </tr>
              <tr>
                <td align="left" colspan="2">Relative thickness of LV wall</td>
                <td align="center">31.9 &#177; 5.42</td>
                <td align="center">32.3 &#177; 6.77</td>
                <td align="center">0.005</td>
              </tr>
              <tr>
                <td align="left" colspan="2">Ejection fraction (%)</td>
                <td align="center">0.66 &#177; 0.06</td>
                <td align="center">0.67 &#177; 0.06</td>
                <td align="center">&lt; 0.001</td>
              </tr>
              <tr>
                <td align="left" colspan="2">Resting LVMSI</td>
                <td align="center">1.039 &#177; 0.141</td>
                <td align="center">1.022 &#177; 0.104</td>
                <td align="center">&lt; 0.001</td>
              </tr>
              <tr>
                <td align="left" colspan="2">Physical effort LVMSI</td>
                <td align="center">1.056 &#177; 0.153</td>
                <td align="center">1.035 &#177; 0.117</td>
                <td align="center">&lt; 0.001</td>
              </tr>
              <tr>
                <td align="left" colspan="5">
                  <bold>ESE Results</bold>
                </td>
              </tr>
              <tr>
                <td align="left">
								</td>
                <td align="left">&#8211; Normal</td>
                <td align="center">71.4%</td>
                <td align="center">78.8%</td>
                <td align="center" rowspan="4">&lt; 0.001</td>
              </tr>
              <tr>
                <td align="left">
								</td>
                <td align="left">&#8211; Ischemic</td>
                <td align="center">12.8%</td>
                <td align="center">10%</td>
              </tr>
              <tr>
                <td align="left">
								</td>
                <td align="left">&#8211; Fixed ischemia</td>
                <td align="center">10.9%</td>
                <td align="center">8.7%</td>
              </tr>
              <tr>
                <td align="left">
								</td>
                <td align="left">&#8211; Fixed and induced ischemia</td>
                <td align="center">4.9%</td>
                <td align="center">2.4%</td>
              </tr>
            </tbody>
          </table>
          <table-wrap-foot>
            <fn id="TFN03">
              <p>LA: left atrium; LV: left ventricle; LVMSI: left ventricle motion score index; ESE: exercise stress echocardiography.</p>
            </fn>
          </table-wrap-foot>
        </table-wrap>
        <p>In the ESE, there was a difference in the left ventricular motion score index in resting and during physical effort. There was also frequent presence of myocardial ischemia in G1 patients.</p>
      </sec>
      <sec>
        <title>Logistic regression analysis</title>
        <p>The test to determine the presence of possible confounders in the model showed that only two variables were independently associated to the occurrence of complications. There was no interaction between the analysed variables (<xref ref-type="table" rid="t4">Table 4</xref>).</p>
        <table-wrap id="t4">
          <label>Table 4</label>
          <caption>
            <title>Multivariate logistic regression with parameters associated to the presence of cardiac arrhythmias during ESE</title>
          </caption>
          <table frame="hsides" rules="groups">
            <colgroup width="25%">
              <col/>
              <col/>
              <col/>
              <col/>
            </colgroup>
            <thead>
              <tr>
                <th align="left">Variable</th>
                <th align="center">Odds Ratio</th>
                <th align="center">CI95%</th>
                <th align="center">p</th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td align="left">Age</td>
                <td align="center">1.04</td>
                <td align="center">1.038 &#8211; 1.049</td>
                <td align="center">&lt; 0.001</td>
              </tr>
              <tr>
                <td align="left">Left Atrium</td>
                <td align="center">1.64</td>
                <td align="center">1.448 &#8211; 1.872</td>
                <td align="center">&lt; 0.001</td>
              </tr>
            </tbody>
          </table>
          <table-wrap-foot>
            <fn id="TFN04">
              <p>CI: confidence interval; LA: left atrium; ESE: exercise stress echocardiography.</p>
            </fn>
          </table-wrap-foot>
        </table-wrap>
      </sec>
    </sec>
    <sec sec-type="discussion">
      <title>Discussion</title>
      <p>ESE proved to be safe in this study, with low frequency of complications, none of which led to death. Death is more frequently observed in SE than in pharmacological stress testing.<xref ref-type="bibr" rid="B29">29</xref> This may be due to the mechanism through which stressor drugs act in the heart: dobutamine stimulates adrenergic receptors, increasing chronotropism and inotropism, and with great arrhythmogenic and hypertensive potential; dipyridamole stresses the heart muscle by stimulating adenosine receptors and reducing subendocardial flow - it also has a negative chronotropic and dromotropic effect as well as bronchoconstrictor activity. However, physical exercise represents a more physiological modality of stress free of the side effects described above.<xref ref-type="bibr" rid="B18">18</xref> There is also a selection bias: candidates eligible for the test physical effort present with preserved ejection fraction, while pharmacological stress testing patients may have more advanced heart diseases.</p>
      <p>In a large multicenter study with 85,997 patients undergoing SE - 26,295 of which were tested by physical stress and the others by pharmacological stress - there was no death outcome in the group tested by ESE. In the pharmacological stress group, however, five deaths were observed. With regards to the frequency of life threatening events, the proportion of the in the ESE group was 1 in 6574, whereas in the group receiving dipyridamole and dobutamine, we saw 1 in every 1294, and 1 in every 557, respectively.<xref ref-type="bibr" rid="B32">32</xref>
			</p>
      <p>In a Moroccan study with 311 patients, 206 of whom were submitted to ESE, no major or lethal events were registered.<xref ref-type="bibr" rid="B33">33</xref> According to Sicari et al.<xref ref-type="bibr" rid="B18">18</xref> pharmacological stress from dobutamine triggers severe complications in 3 of 1,000 patients, and pharmacological stress from dipyridamole triggers severe complications in 1 of 1,000 patients.</p>
      <p>The most frequente minor complications were arrhythmias, especially those with less hemodynamic repercussions and easily reversible upon cessation of effort, such as supraventricular and ventricular extrasystoles. This is according to one study and is not mentioned in other bigger studies.<xref ref-type="bibr" rid="B29">29</xref><sup>,</sup><xref ref-type="bibr" rid="B32">32</xref>
			</p>
      <p>Arterial hypertension due to effort was observed in a significant portion of the sample (9.9% of cases) mostly in chronic hypertensive individuals. One of the reasons for this marked decompensation in the pressure response to stress may be the protocol for exam preparation of our institution, which includes a suspention of beta-blockers for three days prior to the exam. There was a significant difference considering the available literature, which may be because most studies use pharmacological stress, which may have severe hypotension and cardiogenic shock as a response in up to 7.6% of cases.<xref ref-type="bibr" rid="B29">29</xref><sup>,</sup><xref ref-type="bibr" rid="B32">32</xref>
			</p>
      <p>The clinical and demographic profile of the sample is only mentioned by Fennich et al.<xref ref-type="bibr" rid="B33">33</xref> In this study, age was similar to that of this paper (59.2 years of age). However, diabetes mellitus and smoking were more prevalent and SAH was lower, differently from our findings.</p>
      <p>The predictor independent variables, left atrium, and age presented a close relationship with each other. Some studies have reported that the size of the left atrium would naturally increase with age.<xref ref-type="bibr" rid="B37">37</xref><sup>-</sup><xref ref-type="bibr" rid="B39">39</xref> Thus, senescence would provide changes that would culminate with left atrium dilatation and dysfunction, thus increasing predisposition to atrial arrhythmias,<xref ref-type="bibr" rid="B39">39</xref> which may influence their occurrence when the patient is submitted to stress, as in ESE. Still with regards to age, this finding as an independent predictor of complications during ESE is very important, considering this is a commonly observed fact in clinical practice. However, it is not yet described in relation to physical effort in literature.</p>
      <p>Another gap in the literature concerns the relation between the echocardiographic variables and the occurrence of complications during ESE, considering that our study found several significant differences, and there are no studies about them. Another relevant observation is that of a very significant difference in the presence of myocardial ischemia in patients who had adverse events during ESE, maybe due to coronary arterial disease, which alters the cardiac electrical conduction system and induces arrhythmias; a frequently studied event during pharmacological stress, included in the work of Abreu et al.<xref ref-type="bibr" rid="B40">40</xref> but still without supporting evidence for ESE.</p>
      <p>Although current guidelines<xref ref-type="bibr" rid="B41">41</xref> recommend the use of this methodology in moderate-risk patients, in clinical practice we often see it used in high-risk individuals. However, even in those cases, no identifiable complications were found.</p>
      <p>This study shows us interesting data that is still scarcely study in the field of ESE - a method that has been growing due to its versatility, reproducibility, and cost-effectiveness. We expect that this growth prompt new studies around this theme.</p>
      <p>About the limitations of this study, we would highlight those applicable to any observational study, in which unmeasured variables may corroborate the statistical difference between the groups. In this sample, we also find a pre-selection bias, since patients submitted to ESE presented with based heart diseases or fisk factors to their development.</p>
    </sec>
    <sec sec-type="conclusions">
      <title>Conclusion</title>
      <p>ESE is a safe stress modality, with no risk-of-death complications observed. Adverse events recorded were minor and easily reversed by cessation of physical effort. The safety and feasibility of this stress mode associated with its important diagnostic and prognostic validity, justify its use in clinical practice.</p>
    </sec>
  </body>
  <back>
    <fn-group>
      <fn fn-type="supported-by">
        <p>
          <bold>Sources of Funding</bold>
        </p>
        <p>There were no external funding sources for this study.</p>
      </fn>
      <fn fn-type="other">
        <p>
          <bold>Study Association</bold>
        </p>
        <p>This article is part of the thesis of Doctoral submitted by Carlos Jos&#233; Oliveira de Matos and Igor Larchert Mota, from Universidade Federal de Sergipe.</p>
      </fn>
    </fn-group>
    <ref-list>
      <title>References</title>
      <ref id="B1">
        <label>1</label>
        <mixed-citation>1 Rassi A Jr. [Optimization of the medical treatment in coronary artery disease: a task for the subspecialist?]. Arq Bras Cardiol. 2004;83(3):187-8.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Rassi</surname>
              <given-names>A Jr.</given-names>
            </name>
          </person-group>
          <article-title>Optimization of the medical treatment in coronary artery disease: a task for the subspecialist?</article-title>
          <source>Arq Bras Cardiol</source>
          <year>2004</year>
          <volume>83</volume>
          <issue>3</issue>
          <fpage>187</fpage>
          <lpage>188</lpage>
        </element-citation>
      </ref>
      <ref id="B2">
        <label>2</label>
        <mixed-citation>2 Lloyd-Jones D, Adams R, Carnethon M, De Simone G, Ferguson TB, Flegal K, et al; American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics - 2009 update: a report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Circulation. 2009;119(3):480-6. Erratum in: Circulation . 2009;119(3):e182.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Lloyd-Jones</surname>
              <given-names>D</given-names>
            </name>
            <name>
              <surname>Adams</surname>
              <given-names>R</given-names>
            </name>
            <name>
              <surname>Carnethon</surname>
              <given-names>M</given-names>
            </name>
            <name>
              <surname>De Simone</surname>
              <given-names>G</given-names>
            </name>
            <name>
              <surname>Ferguson</surname>
              <given-names>TB</given-names>
            </name>
            <name>
              <surname>Flegal</surname>
              <given-names>K</given-names>
            </name>
            <etal/>
            <collab>American Heart Association Statistics Committee and Stroke Statistics Subcommittee</collab>
          </person-group>
          <article-title>Heart disease and stroke statistics - 2009 update: a report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee</article-title>
          <source>Circulation</source>
          <year>2009</year>
          <volume>119</volume>
          <issue>3</issue>
          <fpage>480</fpage>
          <lpage>486</lpage>
          <comment>Erratum in: Circulation. 2009;119(3):e182</comment>
        </element-citation>
      </ref>
      <ref id="B3">
        <label>3</label>
        <mixed-citation>3 Minist&#233;rio da Sa&#250;de. DATASUS, 2012: Indicadores e dados b&#225;sicos de Sa&#250;de. [citado em 2014 maio 24]. Dispon&#237;vel em: <ext-link ext-link-type="uri" xlink:href="http://tabnet.datasus.gov.br/cgi/idb2012/matriz.htm#mort">http://tabnet.datasus.gov.br/cgi/idb2012/matriz.htm#mort</ext-link>.</mixed-citation>
        <element-citation publication-type="webpage">
          <person-group person-group-type="author">
            <collab>Minist&#233;rio da Sa&#250;de</collab>
          </person-group>
          <source>DATASUS, 2012: Indicadores e dados b&#225;sicos de Sa&#250;de</source>
          <date-in-citation content-type="access-date">2014 maio 24</date-in-citation>
          <comment>Dispon&#237;vel em: <ext-link ext-link-type="uri" xlink:href="http://tabnet.datasus.gov.br/cgi/idb2012/matriz.htm#mort">http://tabnet.datasus.gov.br/cgi/idb2012/matriz.htm#mort</ext-link>
					</comment>
        </element-citation>
      </ref>
      <ref id="B4">
        <label>4</label>
        <mixed-citation>4 Ara&#250;jo AC, Santos BF, Calasans FR, Pinto IM, Oliveira DP, Melo LD, et al. Physical Stress Echocardiography: Prediction of Mortality and Cardiac Events in Patients with Exercise Test showing Ischemia. Arq Bras Cardiol. 2014;103(5):418-25.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Ara&#250;jo</surname>
              <given-names>AC</given-names>
            </name>
            <name>
              <surname>Santos</surname>
              <given-names>BF</given-names>
            </name>
            <name>
              <surname>Calasans</surname>
              <given-names>FR</given-names>
            </name>
            <name>
              <surname>Pinto</surname>
              <given-names>IM</given-names>
            </name>
            <name>
              <surname>Oliveira</surname>
              <given-names>DP</given-names>
            </name>
            <name>
              <surname>Melo</surname>
              <given-names>LD</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Physical Stress Echocardiography: Prediction of Mortality and Cardiac Events in Patients with Exercise Test showing Ischemia</article-title>
          <source>Arq Bras Cardiol</source>
          <year>2014</year>
          <volume>103</volume>
          <issue>5</issue>
          <fpage>418</fpage>
          <lpage>425</lpage>
        </element-citation>
      </ref>
      <ref id="B5">
        <label>5</label>
        <mixed-citation>5 Alves AA. Valor progn&#243;stico da ecocardiografia sob estresse pela dobutamina e adenosina associada &#224; perfus&#227;o mioc&#225;rdica em tempo real em pacientes com doen&#231;a arterial coronariana suspeita ou confirmada. [Tese]. S&#227;o Paulo: Faculdade de Medicina.Universidade de S&#227;o Paulo; 2010.</mixed-citation>
        <element-citation publication-type="thesis">
          <person-group person-group-type="author">
            <name>
              <surname>Alves</surname>
              <given-names>AA</given-names>
            </name>
          </person-group>
          <source>Valor progn&#243;stico da ecocardiografia sob estresse pela dobutamina e adenosina associada &#224; perfus&#227;o mioc&#225;rdica em tempo real em pacientes com doen&#231;a arterial coronariana suspeita ou confirmada</source>
          <comment>Tese</comment>
          <publisher-loc>S&#227;o Paulo</publisher-loc>
          <publisher-name>Faculdade de Medicina.Universidade de S&#227;o Paulo</publisher-name>
          <year>2010</year>
        </element-citation>
      </ref>
      <ref id="B6">
        <label>6</label>
        <mixed-citation>6 Roger VL, Jacobsen SJ, Pellikka PA, Miller TD, Bailey KR, Gersh BJ. Prognostic value of treadmill exercise testing: a population-based study in Olmsted County, Minnesota. Circulation. 1998;98(25):2836-41.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Roger</surname>
              <given-names>VL</given-names>
            </name>
            <name>
              <surname>Jacobsen</surname>
              <given-names>SJ</given-names>
            </name>
            <name>
              <surname>Pellikka</surname>
              <given-names>PA</given-names>
            </name>
            <name>
              <surname>Miller</surname>
              <given-names>TD</given-names>
            </name>
            <name>
              <surname>Bailey</surname>
              <given-names>KR</given-names>
            </name>
            <name>
              <surname>Gersh</surname>
              <given-names>BJ</given-names>
            </name>
          </person-group>
          <article-title>Prognostic value of treadmill exercise testing: a population-based study in Olmsted County, Minnesota</article-title>
          <source>Circulation</source>
          <year>1998</year>
          <volume>98</volume>
          <issue>25</issue>
          <fpage>2836</fpage>
          <lpage>2841</lpage>
        </element-citation>
      </ref>
      <ref id="B7">
        <label>7</label>
        <mixed-citation>7 Secundo PF, Santos BF, Secundo J&#250;nior JA, Silva JB, Souza AR, Faro GB, et al. Clinical and echocardiographic parameters associated with low chronotropic index in non-elderly patients. Arq Bras Cardiol. 2012;98(5):413-20.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Secundo</surname>
              <given-names>PF</given-names>
            </name>
            <name>
              <surname>Santos</surname>
              <given-names>BF</given-names>
            </name>
            <name>
              <surname>Secundo</surname>
              <given-names>JA</given-names>
              <suffix>J&#250;nior</suffix>
            </name>
            <name>
              <surname>Silva</surname>
              <given-names>JB</given-names>
            </name>
            <name>
              <surname>Souza</surname>
              <given-names>AR</given-names>
            </name>
            <name>
              <surname>Faro</surname>
              <given-names>GB</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Clinical and echocardiographic parameters associated with low chronotropic index in non-elderly patients</article-title>
          <source>Arq Bras Cardiol</source>
          <year>2012</year>
          <source>98</source>
          <issue>5</issue>
          <fpage>413</fpage>
          <lpage>420</lpage>
        </element-citation>
      </ref>
      <ref id="B8">
        <label>8</label>
        <mixed-citation>8 Gibbons RJ, Balady GJ, Bricker JT, Chaitman BR, Fletcher GF, Froelicher VF, et al; American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Committee to Update the 1997 Exercise Testing Guidelines. ACC/AHA 2002 guideline update for exercise testing: summary article. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1997 Exercise Testing Guidelines). J Am Coll Cardiol. 2002;40(8):1531-40. Erratum in J Am Coll Cardiol. 2006;48(8):1731.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Gibbons</surname>
              <given-names>RJ</given-names>
            </name>
            <name>
              <surname>Balady</surname>
              <given-names>GJ</given-names>
            </name>
            <name>
              <surname>Bricker</surname>
              <given-names>JT</given-names>
            </name>
            <name>
              <surname>Chaitman</surname>
              <given-names>BR</given-names>
            </name>
            <name>
              <surname>Fletcher</surname>
              <given-names>GF</given-names>
            </name>
            <name>
              <surname>Froelicher</surname>
              <given-names>VF</given-names>
            </name>
            <etal/>
            <collab>American College of Cardiology</collab>
            <collab>American Heart Association Task Force on Practice Guidelines</collab>
          </person-group>
          <article-title>Committee to Update the 1997 Exercise Testing Guidelines. ACC/AHA 2002 guideline update for exercise testing: summary article. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1997 Exercise Testing Guidelines)</article-title>
          <source>J Am Coll Cardiol</source>
          <year>2002</year>
          <volume>40</volume>
          <issue>8</issue>
          <fpage>1531</fpage>
          <lpage>1540</lpage>
          <comment>Erratum in J Am Coll Cardiol. 2006;48(8):1731</comment>
        </element-citation>
      </ref>
      <ref id="B9">
        <label>9</label>
        <mixed-citation>9 Cheitlin MD, Armstrong WF, Aurigemma GP, Beller GA, Bierman FZ, Davis JL, et al. ACC/AHA/ASE 2003 Guideline Update for the Clinical Application of Echocardiography: summary article. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/ASE Committee to Update the 1997 Guidelines for the Clinical Application of Echocardiography). J Am Soc Echocardiogr. 2003;16(10):1091-110.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Cheitlin</surname>
              <given-names>MD</given-names>
            </name>
            <name>
              <surname>Armstrong</surname>
              <given-names>WF</given-names>
            </name>
            <name>
              <surname>Aurigemma</surname>
              <given-names>GP</given-names>
            </name>
            <name>
              <surname>Beller</surname>
              <given-names>GA</given-names>
            </name>
            <name>
              <surname>Bierman</surname>
              <given-names>FZ</given-names>
            </name>
            <name>
              <surname>Davis</surname>
              <given-names>JL</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>ACC/AHA/ASE 2003 Guideline Update for the Clinical Application of Echocardiography: summary article. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/ASE Committee to Update the 1997 Guidelines for the Clinical Application of Echocardiography)</article-title>
          <source>J Am Soc Echocardiogr</source>
          <year>2003</year>
          <volume>16</volume>
          <issue>10</issue>
          <fpage>1091</fpage>
          <lpage>1110</lpage>
        </element-citation>
      </ref>
      <ref id="B10">
        <label>10</label>
        <mixed-citation>10 Picano E; American College of Cadiology; American Heart Association. Stress echocardiography for the diagnosis of coronary artery disease. Indian Heart J. 2003;55(3):223-7.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Picano</surname>
              <given-names>E</given-names>
            </name>
            <collab>American College of Cadiology</collab>
            <collab>American Heart Association</collab>
          </person-group>
          <article-title>Stress echocardiography for the diagnosis of coronary artery disease</article-title>
          <source>Indian Heart J</source>
          <year>2003</year>
          <volume>55</volume>
          <issue>3</issue>
          <fpage>223</fpage>
          <lpage>227</lpage>
        </element-citation>
      </ref>
      <ref id="B11">
        <label>11</label>
        <mixed-citation>11 Calasans FR, Santos BF, Silveira DC, Ara&#250;jo AC, Melo LD, Barreto-Filho JA, et al. Stress echocardiography and major cardiac events in patients with normal exercise test. Arq Bras Cardiol. 2013;101(1):35-42.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Calasans</surname>
              <given-names>FR</given-names>
            </name>
            <name>
              <surname>Santos</surname>
              <given-names>BF</given-names>
            </name>
            <name>
              <surname>Silveira</surname>
              <given-names>DC</given-names>
            </name>
            <name>
              <surname>Ara&#250;jo</surname>
              <given-names>AC</given-names>
            </name>
            <name>
              <surname>Melo</surname>
              <given-names>LD</given-names>
            </name>
            <name>
              <surname>Barreto-Filho</surname>
              <given-names>JA</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Stress echocardiography and major cardiac events in patients with normal exercise test</article-title>
          <source>Arq Bras Cardiol</source>
          <year>2013</year>
          <volume>101</volume>
          <issue>1</issue>
          <fpage>35</fpage>
          <lpage>42</lpage>
        </element-citation>
      </ref>
      <ref id="B12">
        <label>12</label>
        <mixed-citation>12 Oliveira JL, G&#243;es TJ, Santana TA, Travassos TF, Teles LD, Anjos-Andrade FD, et al. Chronotropic incompetence and a higher frequency of myocardial ischemia in exercise echocardiography. Cardiovasc Ultrasound. 2007;5:38.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Oliveira</surname>
              <given-names>JL</given-names>
            </name>
            <name>
              <surname>G&#243;es</surname>
              <given-names>TJ</given-names>
            </name>
            <name>
              <surname>Santana</surname>
              <given-names>TA</given-names>
            </name>
            <name>
              <surname>Travassos</surname>
              <given-names>TF</given-names>
            </name>
            <name>
              <surname>Teles</surname>
              <given-names>LD</given-names>
            </name>
            <name>
              <surname>Anjos-Andrade</surname>
              <given-names>FD</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Chronotropic incompetence and a higher frequency of myocardial ischemia in exercise echocardiography</article-title>
          <source>Cardiovasc Ultrasound</source>
          <year>2007</year>
          <volume>5</volume>
          <fpage>38</fpage>
        </element-citation>
      </ref>
      <ref id="B13">
        <label>13</label>
        <mixed-citation>13 Oliveira JL, Barreto Filho JA, Oliveira GP, Sousa AC. Ecocardiografia sob estresse f&#237;sico - experi&#234;ncia cl&#237;nica e ecocardiogr&#225;fica de uma d&#233;cada. Rev bras ecocardiogr imagem cardiovasc. 2011, 24(1):51-63.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Oliveira</surname>
              <given-names>JL</given-names>
            </name>
            <name>
              <surname>Barreto</surname>
              <given-names>JA</given-names>
              <suffix>Filho</suffix>
            </name>
            <name>
              <surname>Oliveira</surname>
              <given-names>GP</given-names>
            </name>
            <name>
              <surname>Sousa</surname>
              <given-names>AC</given-names>
            </name>
          </person-group>
          <article-title>Ecocardiografia sob estresse f&#237;sico - experi&#234;ncia cl&#237;nica e ecocardiogr&#225;fica de uma d&#233;cada</article-title>
          <source>Rev bras ecocardiogr imagem cardiovasc</source>
          <year>2011</year>
          <volume>24</volume>
          <issue>1</issue>
          <fpage>51</fpage>
          <lpage>63</lpage>
        </element-citation>
      </ref>
      <ref id="B14">
        <label>14</label>
        <mixed-citation>14 Armstrong WF, Pellikka PA, Ryan T, Crouse L, Zogbi WA. Stress echocardiography: recommendations for performance and interpretation of stress echocardiography. Stress Echocardiography Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography. J Am Soc Echocardiogr. 1998;11(1):97-104.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Armstrong</surname>
              <given-names>WF</given-names>
            </name>
            <name>
              <surname>Pellikka</surname>
              <given-names>PA</given-names>
            </name>
            <name>
              <surname>Ryan</surname>
              <given-names>T</given-names>
            </name>
            <name>
              <surname>Crouse</surname>
              <given-names>L</given-names>
            </name>
            <name>
              <surname>Zogbi</surname>
              <given-names>WA</given-names>
            </name>
          </person-group>
          <article-title>Stress echocardiography: recommendations for performance and interpretation of stress echocardiography. Stress Echocardiography Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography</article-title>
          <source>J Am Soc Echocardiogr</source>
          <year>1998</year>
          <volume>11</volume>
          <issue>1</issue>
          <fpage>97</fpage>
          <lpage>104</lpage>
        </element-citation>
      </ref>
      <ref id="B15">
        <label>15</label>
        <mixed-citation>15 Oliveira JL, G&#243;es TJ, Santana TA, Silva IS, Travassos TF, Teles LD, et al. Exercise stress echocardiography in the identification of coronary artery disease in the elderly with chronotropic incompetence. Arq Bras Cardiol. 2007;89(2):100-6,111-8.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Oliveira</surname>
              <given-names>JL</given-names>
            </name>
            <name>
              <surname>G&#243;es</surname>
              <given-names>TJ</given-names>
            </name>
            <name>
              <surname>Santana</surname>
              <given-names>TA</given-names>
            </name>
            <name>
              <surname>Silva</surname>
              <given-names>IS</given-names>
            </name>
            <name>
              <surname>Travassos</surname>
              <given-names>TF</given-names>
            </name>
            <name>
              <surname>Teles</surname>
              <given-names>LD</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Exercise stress echocardiography in the identification of coronary artery disease in the elderly with chronotropic incompetence</article-title>
          <source>Arq Bras Cardiol</source>
          <year>2007</year>
          <volume>89</volume>
          <issue>2</issue>
          <fpage>100</fpage>
          <lpage>118</lpage>
          <page-range>100-6,111-8</page-range>
        </element-citation>
      </ref>
      <ref id="B16">
        <label>16</label>
        <mixed-citation>16 Oliveira JL, Barreto MA, Silva AB, Sousa AC. Stress echocardiography in coronary artery disease. Rev Bras Cir Cardiovasc. 2004;19(1):55-63.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Oliveira</surname>
              <given-names>JL</given-names>
            </name>
            <name>
              <surname>Barreto</surname>
              <given-names>MA</given-names>
            </name>
            <name>
              <surname>Silva</surname>
              <given-names>AB</given-names>
            </name>
            <name>
              <surname>Sousa</surname>
              <given-names>AC</given-names>
            </name>
          </person-group>
          <article-title>Stress echocardiography in coronary artery disease</article-title>
          <source>Rev Bras Cir Cardiovasc</source>
          <year>2004</year>
          <volume>19</volume>
          <issue>1</issue>
          <fpage>55</fpage>
          <lpage>63</lpage>
        </element-citation>
      </ref>
      <ref id="B17">
        <label>17</label>
        <mixed-citation>17 Chagas AC. Doen&#231;a coron&#225;ria. S&#227;o Paulo: Atheneu; 2005. (S&#233;rie Cl&#237;nica M&#233;dica Ci&#234;ncia e Arte).</mixed-citation>
        <element-citation publication-type="book">
          <person-group person-group-type="author">
            <name>
              <surname>Chagas</surname>
              <given-names>AC</given-names>
            </name>
          </person-group>
          <source>Doen&#231;a coron&#225;ria</source>
          <publisher-loc>S&#227;o Paulo</publisher-loc>
          <publisher-name>Atheneu</publisher-name>
          <year>2005</year>
          <comment>(S&#233;rie Cl&#237;nica M&#233;dica Ci&#234;ncia e Arte)</comment>
        </element-citation>
      </ref>
      <ref id="B18">
        <label>18</label>
        <mixed-citation>18 Sicari R, Nihoyannopoulos P, Evangelista A, Kasprzak J, Lancellotti P, Poldermans D, et al; European Association of Echocardiography. Stress Echocardiography Expert Consensus Statement--Executive Summary: European Association of Echocardiography (EAE) (a registered branch of the ESC). Eur Heart J. 2009;30(3):278-89.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Sicari</surname>
              <given-names>R</given-names>
            </name>
            <name>
              <surname>Nihoyannopoulos</surname>
              <given-names>P</given-names>
            </name>
            <name>
              <surname>Evangelista</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Kasprzak</surname>
              <given-names>J</given-names>
            </name>
            <name>
              <surname>Lancellotti</surname>
              <given-names>P</given-names>
            </name>
            <name>
              <surname>Poldermans</surname>
              <given-names>D</given-names>
            </name>
            <etal/>
            <collab>European Association of Echocardiography</collab>
          </person-group>
          <article-title>Stress Echocardiography Expert Consensus Statement--Executive Summary: European Association of Echocardiography (EAE) (a registered branch of the ESC)</article-title>
          <source>Eur Heart J</source>
          <year>2009</year>
          <volume>30</volume>
          <issue>3</issue>
          <fpage>278</fpage>
          <lpage>289</lpage>
        </element-citation>
      </ref>
      <ref id="B19">
        <label>19</label>
        <mixed-citation>19 Ferreira PA, de Lima VC, Campos-Filho O, Gil MA, Cordovil A, Machado CV, et al. Feasibility, safety and accuracy of dobutamine/atropine stress echocardiography for the detection of coronary artery disease in renal transplant candidates. Arq Bras Cardiol. 2007;88(1):45-51.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Ferreira</surname>
              <given-names>PA</given-names>
            </name>
            <name>
              <surname>de Lima</surname>
              <given-names>VC</given-names>
            </name>
            <name>
              <surname>Campos-Filho</surname>
              <given-names>O</given-names>
            </name>
            <name>
              <surname>Gil</surname>
              <given-names>MA</given-names>
            </name>
            <name>
              <surname>Cordovil</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Machado</surname>
              <given-names>CV</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Feasibility, safety and accuracy of dobutamine/atropine stress echocardiography for the detection of coronary artery disease in renal transplant candidates</article-title>
          <source>Arq Bras Cardiol</source>
          <year>2007</year>
          <volume>88</volume>
          <issue>1</issue>
          <fpage>45</fpage>
          <lpage>51</lpage>
        </element-citation>
      </ref>
      <ref id="B20">
        <label>20</label>
        <mixed-citation>20 Picano E, Mathias W Jr, Pingitore A, Bigi R, Previtali M, on behalf of the Echo-Dobutamine International Cooperative Study Group. Safety and tolerability of dobutamine-atropine stress echocardiography: a prospective multicentre study. Echo Dobutamine International Cooperative Study Group. Lancet. 1994;344(8931):1190-2.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Picano</surname>
              <given-names>E</given-names>
            </name>
            <name>
              <surname>Mathias</surname>
              <given-names>W</given-names>
              <suffix>Jr</suffix>
            </name>
            <name>
              <surname>Pingitore</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Bigi</surname>
              <given-names>R</given-names>
            </name>
            <name>
              <surname>Previtali</surname>
              <given-names>M</given-names>
            </name>
            <collab>Echo-Dobutamine International Cooperative Study Group</collab>
          </person-group>
          <article-title>Safety and tolerability of dobutamine-atropine stress echocardiography: a prospective multicentre study.</article-title>
          <publisher-name>Echo Dobutamine International Cooperative Study Group</publisher-name>
          <source>Lancet</source>
          <year>1994</year>
          <volume>344</volume>
          <issue>8931</issue>
          <fpage>1190</fpage>
          <lpage>1192</lpage>
        </element-citation>
      </ref>
      <ref id="B21">
        <label>21</label>
        <mixed-citation>21 Pinton R, Lemke W, Garcia LG. [Symptoms, complications and hemodynamic changes related to dobutamine stress echocardiography]. Arq Bras Cardiol. 1997;69(3):161-4.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Pinton</surname>
              <given-names>R</given-names>
            </name>
            <name>
              <surname>Lemke</surname>
              <given-names>W</given-names>
            </name>
            <name>
              <surname>Garcia</surname>
              <given-names>LG</given-names>
            </name>
          </person-group>
          <article-title>Symptoms, complications and hemodynamic changes related to dobutamine stress echocardiography</article-title>
          <source>Arq Bras Cardiol</source>
          <year>1997</year>
          <volume>69</volume>
          <issue>3</issue>
          <fpage>161</fpage>
          <lpage>164</lpage>
        </element-citation>
      </ref>
      <ref id="B22">
        <label>22</label>
        <mixed-citation>22 Cortigiani L, Picano E, Coletta C, Chiarella F, Mathias W, Gandolfo N, et al; Echo Persantine International Cooperative (EPIC) Study Group; Echo Dobutamine International Cooperative (EDIC) Study Group. Safety, feasibility, and prognostic implications of pharmacologic stress echocardiography in 1482 patients evaluated in an ambulatory setting. Am Heart J. 2001;141(4):621-9.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Cortigiani</surname>
              <given-names>L</given-names>
            </name>
            <name>
              <surname>Picano</surname>
              <given-names>E</given-names>
            </name>
            <name>
              <surname>Coletta</surname>
              <given-names>C</given-names>
            </name>
            <name>
              <surname>Chiarella</surname>
              <given-names>F</given-names>
            </name>
            <name>
              <surname>Mathias</surname>
              <given-names>W</given-names>
            </name>
            <name>
              <surname>Gandolfo</surname>
              <given-names>N</given-names>
            </name>
            <etal/>
            <collab>Echo Persantine International Cooperative (EPIC) Study Group</collab>
            <collab>Echo Dobutamine International Cooperative (EDIC) Study Group</collab>
          </person-group>
          <article-title>Safety, feasibility, and prognostic implications of pharmacologic stress echocardiography in 1482 patients evaluated in an ambulatory setting</article-title>
          <source>Am Heart J</source>
          <year>2001</year>
          <volume>141</volume>
          <issue>4</issue>
          <fpage>621</fpage>
          <lpage>629</lpage>
        </element-citation>
      </ref>
      <ref id="B23">
        <label>23</label>
        <mixed-citation>23 Abreu JS, Di&#243;genes TC, Farias AG, Morais JM, Paes Junior JN. [Safety and feasibility of dobutamine-atropine stress echocardiography in octogenarian patients]. Arq Bras Cardiol. 2005;85(3):198-204.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Abreu</surname>
              <given-names>JS</given-names>
            </name>
            <name>
              <surname>Di&#243;genes</surname>
              <given-names>TC</given-names>
            </name>
            <name>
              <surname>Farias</surname>
              <given-names>AG</given-names>
            </name>
            <name>
              <surname>Morais</surname>
              <given-names>JM</given-names>
            </name>
            <name>
              <surname>Paes</surname>
              <given-names>JN</given-names>
              <suffix>Junior</suffix>
            </name>
          </person-group>
          <article-title>Safety and feasibility of dobutamine-atropine stress echocardiography in octogenarian patients</article-title>
          <source>Arq Bras Cardiol</source>
          <year>2005</year>
          <volume>85</volume>
          <issue>3</issue>
          <fpage>198</fpage>
          <lpage>1204</lpage>
        </element-citation>
      </ref>
      <ref id="B24">
        <label>24</label>
        <mixed-citation>24 Secknus MA, Marwick TH. Evolution of dobutamine echocardiography protocols and indications: safety and side effects in 3,011 studies over 5 years. J Am Coll Cardiol. 1997;29(6):1234-40.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Secknus</surname>
              <given-names>MA</given-names>
            </name>
            <name>
              <surname>Marwick</surname>
              <given-names>TH</given-names>
            </name>
          </person-group>
          <article-title>Evolution of dobutamine echocardiography protocols and indications: safety and side effects in 3,011 studies over 5 years</article-title>
          <source>J Am Coll Cardiol</source>
          <year>1997</year>
          <volume>29</volume>
          <issue>6</issue>
          <fpage>1234</fpage>
          <lpage>1240</lpage>
        </element-citation>
      </ref>
      <ref id="B25">
        <label>25</label>
        <mixed-citation>25 Mathias W Jr, Arruda A, Santos FC, Arruda A L, Mattos E, Osorio A, et al. Safety of dobutamine-atropine stress echocardiography: a prospective experience of 4,033 consecutive studies. J Am Soc Echocardiogr. 1999;12(10):785-91.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Mathias</surname>
              <given-names>W</given-names>
              <suffix>Jr</suffix>
            </name>
            <name>
              <surname>Arruda</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Santos</surname>
              <given-names>FC</given-names>
            </name>
            <name>
              <surname>Arruda</surname>
              <given-names>A L</given-names>
            </name>
            <name>
              <surname>Mattos</surname>
              <given-names>E</given-names>
            </name>
            <name>
              <surname>Osorio</surname>
              <given-names>A</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Safety of dobutamine-atropine stress echocardiography: a prospective experience of 4,033 consecutive studies</article-title>
          <source>J Am Soc Echocardiogr</source>
          <year>1999</year>
          <volume>12</volume>
          <issue>10</issue>
          <fpage>785</fpage>
          <lpage>791</lpage>
        </element-citation>
      </ref>
      <ref id="B26">
        <label>26</label>
        <mixed-citation>26 Lette J, Tatum JL, Fraser S, Miller DD, Waters DD, Heller G, et al. Safety of dipyridamole testing in 73,806 patients: the Multicenter Dipyridamole Safety Study. J Nucl Cardiol. 1995;2(1):3-17.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Lette</surname>
              <given-names>J</given-names>
            </name>
            <name>
              <surname>Tatum</surname>
              <given-names>JL</given-names>
            </name>
            <name>
              <surname>Fraser</surname>
              <given-names>S</given-names>
            </name>
            <name>
              <surname>Miller</surname>
              <given-names>DD</given-names>
            </name>
            <name>
              <surname>Waters</surname>
              <given-names>DD</given-names>
            </name>
            <name>
              <surname>Heller</surname>
              <given-names>G</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Safety of dipyridamole testing in 73,806 patients: the Multicenter Dipyridamole Safety Study</article-title>
          <source>J Nucl Cardiol</source>
          <year>1995</year>
          <volume>2</volume>
          <issue>1</issue>
          <fpage>3</fpage>
          <lpage>17</lpage>
        </element-citation>
      </ref>
      <ref id="B27">
        <label>27</label>
        <mixed-citation>27 Beckmann S, Haug G. National registry 1995-1998 on 150.000 stress echo examinations: side effects and complications in 60.448 examinations of the registry 1997-1998 (abstract). Circulation. 1999;100(Suppl):3401A.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Beckmann</surname>
              <given-names>S</given-names>
            </name>
            <name>
              <surname>Haug</surname>
              <given-names>G</given-names>
            </name>
          </person-group>
          <article-title>National registry 1995-1998 on 150.000 stress echo examinations: side effects and complications in 60.448 examinations of the registry 1997-1998 (abstract)</article-title>
          <source>Circulation</source>
          <year>1999</year>
          <volume>100</volume>
          <supplement>Suppl</supplement>
          <fpage>3401A</fpage>
        </element-citation>
      </ref>
      <ref id="B28">
        <label>28</label>
        <mixed-citation>28 Tsutsui JM, Osorio A F, Lario FA, Fernandes DR, Sodre G, Andrade JL, et al. Comparison of safety and efficacy of the early injection of atropine during dobutamine stress echocardiography with the conventional protocol. Am J Cardiol. 2004;94(11):1367-72.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Tsutsui</surname>
              <given-names>JM</given-names>
            </name>
            <name>
              <surname>Osorio</surname>
              <given-names>A F</given-names>
            </name>
            <name>
              <surname>Lario</surname>
              <given-names>FA</given-names>
            </name>
            <name>
              <surname>Fernandes</surname>
              <given-names>DR</given-names>
            </name>
            <name>
              <surname>Sodre</surname>
              <given-names>G</given-names>
            </name>
            <name>
              <surname>Andrade</surname>
              <given-names>JL</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Comparison of safety and efficacy of the early injection of atropine during dobutamine stress echocardiography with the conventional protocol</article-title>
          <source>Am J Cardiol</source>
          <year>2004</year>
          <volume>94</volume>
          <issue>11</issue>
          <fpage>1367</fpage>
          <lpage>1372</lpage>
        </element-citation>
      </ref>
      <ref id="B29">
        <label>29</label>
        <mixed-citation>29 Geleijnse ML, Krenning BJ, Nemes A, van Dalen BM, Soliman OI, Ten Cate FJ, et al. Incidence, pathophysiology, and treatment of complications during dobutamine-atropine stress echocardiography. Circulation 2010;121(15):1756-67.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Geleijnse</surname>
              <given-names>ML</given-names>
            </name>
            <name>
              <surname>Krenning</surname>
              <given-names>BJ</given-names>
            </name>
            <name>
              <surname>Nemes</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>van Dalen</surname>
              <given-names>BM</given-names>
            </name>
            <name>
              <surname>Soliman</surname>
              <given-names>OI</given-names>
            </name>
            <name>
              <surname>Ten Cate</surname>
              <given-names>FJ</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Incidence, pathophysiology, and treatment of complications during dobutamine-atropine stress echocardiography</article-title>
          <source>Circulation</source>
          <year>2010</year>
          <volume>121</volume>
          <issue>15</issue>
          <fpage>1756</fpage>
          <lpage>1767</lpage>
        </element-citation>
      </ref>
      <ref id="B30">
        <label>30</label>
        <mixed-citation>30 Beleslin BD, Ostojic M, Stepanovic J, Djordjevic-Dikic A, Stojkovic S, Nedeljkovic M, et al. Stress echocardiography in the detection of myocardial ischaemia. Head-to-head comparison of exercise, dobutamine, and dipyridamole tests. Circulation. 1994;90(3):1168-76.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Beleslin</surname>
              <given-names>BD</given-names>
            </name>
            <name>
              <surname>Ostojic</surname>
              <given-names>M</given-names>
            </name>
            <name>
              <surname>Stepanovic</surname>
              <given-names>J</given-names>
            </name>
            <name>
              <surname>Djordjevic-Dikic</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Stojkovic</surname>
              <given-names>S</given-names>
            </name>
            <name>
              <surname>Nedeljkovic</surname>
              <given-names>M</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Stress echocardiography in the detection of myocardial ischaemia. Head-to-head comparison of exercise, dobutamine, and dipyridamole tests</article-title>
          <source>Circulation</source>
          <year>1994</year>
          <volume>90</volume>
          <issue>3</issue>
          <fpage>1168</fpage>
          <lpage>1176</lpage>
        </element-citation>
      </ref>
      <ref id="B31">
        <label>31</label>
        <mixed-citation>31 Santana JS, Franco Filho JC, S&#225; Neto AA, Melo EV, Santana NO, Barreto AT, et al. Prognostic value of chronotropic incompetence in elderly patients undergoing exercise echocardiography. Arq Bras Cardiol. 2013;100(5):429-36.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Santana</surname>
              <given-names>JS</given-names>
            </name>
            <name>
              <surname>Franco</surname>
              <given-names>JC</given-names>
              <suffix>Filho</suffix>
            </name>
            <name>
              <surname>S&#225;</surname>
              <given-names>AA</given-names>
              <suffix>Neto</suffix>
            </name>
            <name>
              <surname>Melo</surname>
              <given-names>EV</given-names>
            </name>
            <name>
              <surname>Santana</surname>
              <given-names>NO</given-names>
            </name>
            <name>
              <surname>Barreto</surname>
              <given-names>AT</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Prognostic value of chronotropic incompetence in elderly patients undergoing exercise echocardiography</article-title>
          <source>Arq Bras Cardiol</source>
          <year>2013</year>
          <volume>100</volume>
          <issue>5</issue>
          <fpage>429</fpage>
          <lpage>436</lpage>
        </element-citation>
      </ref>
      <ref id="B32">
        <label>32</label>
        <mixed-citation>32 Varga A, Rodriguez Garcia MA, Picano E; International Stress Echo Complication Registry. Safety of stress echocardiography (from the international stress echo complication registry). Am J Cardiol. 2006;98(4):541-3.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Varga</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Rodriguez Garcia</surname>
              <given-names>MA</given-names>
            </name>
            <name>
              <surname>Picano</surname>
              <given-names>E</given-names>
            </name>
            <collab>International Stress Echo Complication Registry</collab>
          </person-group>
          <article-title>Safety of stress echocardiography (from the international stress echo complication registry)</article-title>
          <source>Am J Cardiol</source>
          <year>2006</year>
          <volume>98</volume>
          <issue>4</issue>
          <fpage>541</fpage>
          <lpage>543</lpage>
        </element-citation>
      </ref>
      <ref id="B33">
        <label>33</label>
        <mixed-citation>33 Fennich N, Ellouali F, Abdelali S, Chaara A, Berrada A, Elhajjaji I, et al. Stress echocardiography: safety and tolerability. Cardiovasc Ultrasound. 2013,11:30.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Fennich</surname>
              <given-names>N</given-names>
            </name>
            <name>
              <surname>Ellouali</surname>
              <given-names>F</given-names>
            </name>
            <name>
              <surname>Abdelali</surname>
              <given-names>S</given-names>
            </name>
            <name>
              <surname>Chaara</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Berrada</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Elhajjaji</surname>
              <given-names>I</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Stress echocardiography: safety and tolerability</article-title>
          <source>Cardiovasc Ultrasound</source>
          <year>2013</year>
          <volume>11</volume>
          <fpage>30</fpage>
        </element-citation>
      </ref>
      <ref id="B34">
        <label>34</label>
        <mixed-citation>34 Lauer MS, Francis GS, Okin PM, Pashkow FJ, Snader CE, Marwick TH. Impaired chronotropic response to exercise stress testing as a predictor of mortality. JAMA. 1999;281(6):524-9.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Lauer</surname>
              <given-names>MS</given-names>
            </name>
            <name>
              <surname>Francis</surname>
              <given-names>GS</given-names>
            </name>
            <name>
              <surname>Okin</surname>
              <given-names>PM</given-names>
            </name>
            <name>
              <surname>Pashkow</surname>
              <given-names>FJ</given-names>
            </name>
            <name>
              <surname>Snader</surname>
              <given-names>CE</given-names>
            </name>
            <name>
              <surname>Marwick</surname>
              <given-names>TH</given-names>
            </name>
          </person-group>
          <article-title>Impaired chronotropic response to exercise stress testing as a predictor of mortality</article-title>
          <source>JAMA</source>
          <year>1999</year>
          <volume>281</volume>
          <issue>6</issue>
          <fpage>524</fpage>
          <lpage>529</lpage>
        </element-citation>
      </ref>
      <ref id="B35">
        <label>35</label>
        <mixed-citation>35 Whaley MH, Brubaker PH, Otto R. (eds.). ACSM's guidelines for exercise testing and prescription. 7th ed. Philadelphia: Lippincott Williams &amp; Wilkins; 2007.</mixed-citation>
        <element-citation publication-type="book">
          <person-group person-group-type="editor">
            <name>
              <surname>Whaley</surname>
              <given-names>MH</given-names>
            </name>
            <name>
              <surname>Brubaker</surname>
              <given-names>PH</given-names>
            </name>
            <name>
              <surname>Otto</surname>
              <given-names>R</given-names>
            </name>
          </person-group>
          <source>ACSM's guidelines for exercise testing and prescription</source>
          <edition>7th ed</edition>
          <publisher-loc>Philadelphia</publisher-loc>
          <publisher-name>Lippincott Williams &amp; Wilkins</publisher-name>
          <year>2007</year>
        </element-citation>
      </ref>
      <ref id="B36">
        <label>36</label>
        <mixed-citation>36 Schiller NB, Shah PM, Crawford M, DeMaria A, Devereux R, Feigenbaum H, et al. Recommendations for quantitation of the left ventricle by two dimensional echocardiography. American Society of Echocardiography Committee on Standards, Subcommittee on Quantitation of Two-Dimensional Echocardiograms. J Am Soc Echocardiogr. 1989;2(5):358-67.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Schiller</surname>
              <given-names>NB</given-names>
            </name>
            <name>
              <surname>Shah</surname>
              <given-names>PM</given-names>
            </name>
            <name>
              <surname>Crawford</surname>
              <given-names>M</given-names>
            </name>
            <name>
              <surname>DeMaria</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Devereux</surname>
              <given-names>R</given-names>
            </name>
            <name>
              <surname>Feigenbaum</surname>
              <given-names>H</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Recommendations for quantitation of the left ventricle by two dimensional echocardiography. American Society of Echocardiography Committee on Standards, Subcommittee on Quantitation of Two-Dimensional Echocardiograms</article-title>
          <source>J Am Soc Echocardiogr</source>
          <year>1989</year>
          <volume>2</volume>
          <issue>5</issue>
          <fpage>358</fpage>
          <lpage>367</lpage>
        </element-citation>
      </ref>
      <ref id="B37">
        <label>37</label>
        <mixed-citation>37 Gardin JM, Henry WL, Savage DD, Ware JH, Burn C, Borer JS. Echocardiographic measurements in normal subjects: evaluation of an adult population without clinically apparent heart disease. J Clin Ultrasound. 1979;7(6):439-47.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Gardin</surname>
              <given-names>JM</given-names>
            </name>
            <name>
              <surname>Henry</surname>
              <given-names>WL</given-names>
            </name>
            <name>
              <surname>Savage</surname>
              <given-names>DD</given-names>
            </name>
            <name>
              <surname>Ware</surname>
              <given-names>JH</given-names>
            </name>
            <name>
              <surname>Burn</surname>
              <given-names>C</given-names>
            </name>
            <name>
              <surname>Borer</surname>
              <given-names>JS</given-names>
            </name>
          </person-group>
          <article-title>Echocardiographic measurements in normal subjects: evaluation of an adult population without clinically apparent heart disease</article-title>
          <source>J Clin Ultrasound</source>
          <year>1979</year>
          <volume>7</volume>
          <issue>6</issue>
          <fpage>439</fpage>
          <lpage>447</lpage>
        </element-citation>
      </ref>
      <ref id="B38">
        <label>38</label>
        <mixed-citation>38 Triposkiadis F, Tentolouris K, Androulakis A, Trikas A, Toutouzas K, Kyriakidis M, et al. Left atrial mechanical function in the health elderly: new insights from a combined assessment of changes in atrial volumes and transmitral flow velocity. J Am Soc Echocardiogr. 1995;8(6):801-9.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Triposkiadis</surname>
              <given-names>F</given-names>
            </name>
            <name>
              <surname>Tentolouris</surname>
              <given-names>K</given-names>
            </name>
            <name>
              <surname>Androulakis</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Trikas</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Toutouzas</surname>
              <given-names>K</given-names>
            </name>
            <name>
              <surname>Kyriakidis</surname>
              <given-names>M</given-names>
            </name>
            <etal/>
          </person-group>
          <article-title>Left atrial mechanical function in the health elderly: new insights from a combined assessment of changes in atrial volumes and transmitral flow velocity</article-title>
          <source>J Am Soc Echocardiogr</source>
          <year>1995</year>
          <volume>8</volume>
          <issue>6</issue>
          <fpage>801</fpage>
          <lpage>809</lpage>
        </element-citation>
      </ref>
      <ref id="B39">
        <label>39</label>
        <mixed-citation>39 Sousa AC. Left atrial volume as an index of diastolic function. Arq Bras Cardiol. 2006;87(3):e27-33.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Sousa</surname>
              <given-names>AC</given-names>
            </name>
          </person-group>
          <article-title>Left atrial volume as an index of diastolic function</article-title>
          <source>Arq Bras Cardiol</source>
          <year>2006</year>
          <volume>87</volume>
          <issue>3</issue>
          <fpage>e27</fpage>
          <lpage>e33</lpage>
        </element-citation>
      </ref>
      <ref id="B40">
        <label>40</label>
        <mixed-citation>40 Abreu JS, Di&#243;genes TC, Farias AG, Carneiro MM, Morais JM, Paes Junior JN. Arritmias complexas que surgem durante o ecocardiograma sob estresse com dobutamina e atropina. Revista Brasileira de Ecocardiografia. 2007;20(1):24-33.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Abreu</surname>
              <given-names>JS</given-names>
            </name>
            <name>
              <surname>Di&#243;genes</surname>
              <given-names>TC</given-names>
            </name>
            <name>
              <surname>Farias</surname>
              <given-names>AG</given-names>
            </name>
            <name>
              <surname>Carneiro</surname>
              <given-names>MM</given-names>
            </name>
            <name>
              <surname>Morais</surname>
              <given-names>JM</given-names>
            </name>
            <name>
              <surname>Paes</surname>
              <given-names>JN</given-names>
              <suffix>Junior</suffix>
            </name>
          </person-group>
          <article-title>Arritmias complexas que surgem durante o ecocardiograma sob estresse com dobutamina e atropina</article-title>
          <source>Revista Brasileira de Ecocardiografia</source>
          <year>2007</year>
          <volume>20</volume>
          <issue>1</issue>
          <fpage>24</fpage>
          <lpage>33</lpage>
        </element-citation>
      </ref>
      <ref id="B41">
        <label>41</label>
        <mixed-citation>41 Cesar LA, Ferreira JF, Armaganijan D, Gowdak LH, Mansur AP, Bodanese LC, et al./ Brazilian Society of Cardiology. Diretriz de doen&#231;a coron&#225;ria est&#225;vel. Arq Bras Cardiol. 2014;103(2Supl.2):1-59.</mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Cesar</surname>
              <given-names>LA</given-names>
            </name>
            <name>
              <surname>Ferreira</surname>
              <given-names>JF</given-names>
            </name>
            <name>
              <surname>Armaganijan</surname>
              <given-names>D</given-names>
            </name>
            <name>
              <surname>Gowdak</surname>
              <given-names>LH</given-names>
            </name>
            <name>
              <surname>Mansur</surname>
              <given-names>AP</given-names>
            </name>
            <name>
              <surname>Bodanese</surname>
              <given-names>LC</given-names>
            </name>
            <etal/>
            <collab>Brazilian Society of Cardiology</collab>
          </person-group>
          <article-title>Diretriz de doen&#231;a coron&#225;ria est&#225;vel</article-title>
          <source>Arq Bras Cardiol</source>
          <year>2014</year>
          <volume>103</volume>
          <issue>2</issue>
          <supplement>Supl.2</supplement>
          <fpage>1</fpage>
          <lpage>59</lpage>
        </element-citation>
      </ref>
    </ref-list>
  </back>
  <sub-article article-type="translation" id="s1" xml:lang="pt">
    <front-stub>
      <title-group>
        <article-title>Baixa Preval&#234;ncia de Eventos Adversos Maiores &#224; Ecocardiografia sob Estresse F&#237;sico</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <name>
            <surname>Andrade</surname>
            <given-names>Stephanie Macedo</given-names>
          </name>
          <xref ref-type="aff" rid="aff3">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Telino</surname>
            <given-names>Caio Jos&#233; Coutinho Leal</given-names>
          </name>
          <xref ref-type="aff" rid="aff3">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Sousa</surname>
            <given-names>Ant&#244;nio Carlos Sobral</given-names>
          </name>
          <xref ref-type="aff" rid="aff3">1</xref>
          <xref ref-type="aff" rid="aff4">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Melo</surname>
            <given-names>Enaldo Vieira de</given-names>
          </name>
          <xref ref-type="aff" rid="aff3">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Teixeira</surname>
            <given-names>Carla Carolina Cardoso</given-names>
          </name>
          <xref ref-type="aff" rid="aff3">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Teixeira</surname>
            <given-names>Clarissa Karine Cardoso</given-names>
          </name>
          <xref ref-type="aff" rid="aff3">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Santana</surname>
            <given-names>Jaquiele Santos</given-names>
          </name>
          <xref ref-type="aff" rid="aff3">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Mota</surname>
            <given-names>Igor Larchert</given-names>
          </name>
          <xref ref-type="aff" rid="aff3">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Matos</surname>
            <given-names>Carlos Jos&#233; Oliveira de</given-names>
          </name>
          <xref ref-type="aff" rid="aff3">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Oliveira</surname>
            <given-names>Joselina Luzia Menezes</given-names>
          </name>
          <xref ref-type="aff" rid="aff3">1</xref>
          <xref ref-type="aff" rid="aff4">2</xref>
          <xref ref-type="corresp" rid="c2"/>
        </contrib>
      </contrib-group>
      <aff id="aff3">
        <label>1</label>
        <institution content-type="original">Universidade Federal de Sergipe, Aracaju, SE - Brasil</institution>
      </aff>
      <aff id="aff4">
        <label>2</label>
        <institution content-type="original">Centro de Ensino e Pesquisa e Laborat&#243;rio de Ecocardiografia (ECOLAB) do Hospital e Funda&#231;&#227;o S&#227;o Lucas, Aracaju, SE - Brasil</institution>
      </aff>
      <author-notes>
        <corresp id="c2"><bold>Correspond&#234;ncia: Joselina Luzia Menezes Oliveira</bold>. Pra&#231;a Graccho Cardoso, 76/402, S&#227;o Jos&#233;. CEP 49015-180, Aracaju, SE &#8211; Brasil E-mail: <email>jlobelem@cardiol.br</email>, <email>joselinamenezes@gmail.com</email>
				</corresp>
        <fn fn-type="con">
          <p>
            <bold>Contribui&#231;&#227;o dos autores</bold>
          </p>
          <p>Concep&#231;&#227;o e desenho da pesquisa: Andrade SM, Sousa ACS, Melo EV, Teixeira CCC, Teixeira CKC, Santana JS, Mota IL, Matos CJO, Oliveira JLM. Obten&#231;&#227;o de dados: Andrade SM, Telino CJCL, Teixeira CCC, Teixeira CKC, Santana JS, Mota IL, Matos CJO, Oliveira JLM. An&#225;lise e interpreta&#231;&#227;o dos dados: Andrade SM, Sousa ACS, Melo EV, Oliveira JLM. An&#225;lise estat&#237;stica: Melo EV, Matos CJO, Oliveira JLM. Reda&#231;&#227;o do manuscrito: Andrade SM, Telino CJCL, Sousa ACS. Revis&#227;o cr&#237;tica do manuscrito quanto ao conte&#250;do intelectual importante: Andrade SM, Sousa ACS, Matos CJO, Oliveira JLM. Supervis&#227;o / como investigador principal: Andrade SM, Oliveira JLM.</p>
        </fn>
        <fn fn-type="conflict">
          <p>
            <bold>Potencial Conflito de Interesse</bold>
          </p>
          <p>Declaro n&#227;o haver conflito de interesses pertinentes.</p>
        </fn>
      </author-notes>
      <abstract>
        <title>Resumo</title>
        <sec>
          <title>Fundamento:</title>
          <p>A ecocardiografia sob estresse constitui metodologia validada para diagn&#243;stico e estratifica&#231;&#227;o de risco da doen&#231;a arterial coron&#225;ria. A ecocardiografia sob estresse f&#237;sico (EEF) tem se destacado como a mais fisiol&#243;gica dentre as modalidades de estresse, todavia sua seguran&#231;a n&#227;o est&#225; bem estabelecida.</p>
        </sec>
        <sec>
          <title>Objetivo: </title>
          <p>Estudar as complica&#231;&#245;es relacionadas &#224; EEF e as vari&#225;veis cl&#237;nicas e ecocardiogr&#225;ficas preditoras dessas ocorr&#234;ncias.</p>
        </sec>
        <sec>
          <title>M&#233;todo:</title>
          <p>Estudo transversal composto por 10250 pacientes submetidos &#224; EEF por conveni&#234;ncia, de janeiro de 2000 a junho de 2014. As arritmias card&#237;acas (AC) foram as complica&#231;&#245;es mais frequentemente encontradas durante o exame. Os volunt&#225;rios foramdivididos em dois grupos, de acordo com a ocorr&#234;ncia de AC &#224; EEF: grupo G1 - composto por pacientes que apresentaram AC e grupo G2 - formado por indiv&#237;duos que n&#227;o exibiram tal complica&#231;&#227;o.</p>
        </sec>
        <sec>
          <title>Resultados:</title>
          <p>O grupo G1 com 2843 (27,7%) pacientes, e grupo G2 formado por 7407 (72,3%). N&#227;o foram registrados &#243;bitos, infarto agudo do mioc&#225;rdio, assistolia ou fibrila&#231;&#227;o ventricular. As extrass&#237;stoles supraventriculares (13,7%) e as ventriculares (11,5%) foram as AC predominantes. O grupo G1 apresentou idade m&#233;dia mais elevada, maior frequ&#234;ncia de hipertens&#227;o arterial sist&#234;mica e tabagismo, maiores dimens&#245;es da raiz da aorta e do &#225;trio esquerdo (AE) e menor fra&#231;&#227;o de eje&#231;&#227;o do ventr&#237;culo esquerdo que o G2. O grupo G1 exibiu tamb&#233;m, mais altera&#231;&#245;es isqu&#234;micas (p &lt; 0,001). As vari&#225;veis preditoras foram idade (RR 1,04; [IC] 95% 1,038 - 1,049) e AE (RR 1,64; [IC] 95% 1,448 - 1,872).</p>
        </sec>
        <sec>
          <title>Conclus&#227;o:</title>
          <p>A presente investiga&#231;&#227;o demonstrou que a EEF &#233; uma modalidade segura, ocorrendo apenas complica&#231;&#245;es n&#227;o-fatais. Idade avan&#231;ada e aumento da dimens&#227;o do AE s&#227;o preditores da presen&#231;a de arritmias card&#237;acas.</p>
        </sec>
      </abstract>
      <kwd-group xml:lang="pt">
        <title>Palavras-chave:</title>
        <kwd>Doen&#231;a da Arterial Coronariana</kwd>
        <kwd>Exerc&#237;cio / fisiologia</kwd>
        <kwd>Ecocardiografia Sob Estresse</kwd>
        <kwd>Teste de Esfor&#231;o</kwd>
        <kwd>Seguran&#231;a</kwd>
      </kwd-group>
    </front-stub>
    <body>
      <sec sec-type="intro">
        <title>Introdu&#231;&#227;o</title>
        <p>A doen&#231;a arterial coronariana (DAC) constitui a principal causa de morbimortalidade no mundo.<xref ref-type="bibr" rid="B1">1</xref><sup>,</sup><xref ref-type="bibr" rid="B2">2</xref> No Brasil, anualmente,<xref ref-type="bibr" rid="B3">3</xref> as doen&#231;as cardiovasculares (DCV) s&#227;o respons&#225;veis por mais de um ter&#231;o das mortes. Devido ao grande impacto social, a avalia&#231;&#227;o precoce da DAC tornou-se, ent&#227;o, mandat&#243;ria, a fim de se identificar, n&#227;o somente um grupo de alto risco, nos quais interven&#231;&#245;es adicionais s&#227;o necess&#225;rias, mas tamb&#233;m selecionar um subgrupo de baixo risco, no qual procedimentos adicionais seriam dispens&#225;veis.<xref ref-type="bibr" rid="B4">4</xref><sup>,</sup><xref ref-type="bibr" rid="B5">5</xref>
				</p>
        <p>O teste ergom&#233;trico (TE) &#233; o exame n&#227;o invasivo recomendado inicialmente para o diagn&#243;stico e a estratifica&#231;&#227;o de risco de pacientes com suspeita de DAC.<xref ref-type="bibr" rid="B6">6</xref><sup>-</sup><xref ref-type="bibr" rid="B8">8</xref> Entretanto, tal metodologia apresenta limita&#231;&#245;es em certas situa&#231;&#245;es como a da presen&#231;a de bloqueio de ramo esquerdo ou presen&#231;a de altera&#231;&#245;es do segmento ST no eletrocardiograma (ECG) de repouso.<xref ref-type="bibr" rid="B8">8</xref> Al&#233;m disso, as altera&#231;&#245;es da motilidade segmentar do ventr&#237;culo esquerdo, detectadas a partir da ecocardiografia sob estresse (EE), aparecem mais precocemente na cascata isqu&#234;mica do que a angina ou altera&#231;&#245;es do segmento ST, conferindo maior sensibilidade e especificidade &#224; EE.<xref ref-type="bibr" rid="B9">9</xref><sup>-</sup><xref ref-type="bibr" rid="B12">12</xref>
				</p>
        <p>A EE, introduzida desde o final da d&#233;cada de 70, inicialmente sob a forma de estresse farmacol&#243;gico, &#233; metodologia bem validada para diagn&#243;stico, estratifica&#231;&#227;o de risco, progn&#243;stico e avalia&#231;&#227;o da viabilidade mioc&#225;rdica em coronariopatas.<xref ref-type="bibr" rid="B13">13</xref><sup>-</sup><xref ref-type="bibr" rid="B18">18</xref> Apesar de a utiliza&#231;&#227;o de f&#225;rmacos como estressores ter se revelado um procedimento seguro, ultimamente a literatura especializada tem dado grande enfoque ao estudo das complica&#231;&#245;es dessa pr&#225;tica.<xref ref-type="bibr" rid="B19">19</xref><sup>-</sup><xref ref-type="bibr" rid="B29">29</xref>
				</p>
        <p>Ainda que apresentem acur&#225;cia semelhante em pacientes com capacidade f&#237;sica preservada, a ecocardiografia sob estresse f&#237;sico (EEF) &#233; a pr&#225;tica de primeira escolha, reservando-se a farmacol&#243;gica para aquele indiv&#237;duo incapaz ou pouco motivado a se exercitar adequadamente.<xref ref-type="bibr" rid="B30">30</xref><sup>,</sup><xref ref-type="bibr" rid="B31">31</xref> A EEF tamb&#233;m se apresenta como metodologia fisiol&#243;gica e vers&#225;til, cuja utiliza&#231;&#227;o tem crescido recentemente, por&#233;m, s&#227;o escassos os trabalhos na literatura que abordem a seguran&#231;a do m&#233;todo e suas complica&#231;&#245;es.<xref ref-type="bibr" rid="B32">32</xref><sup>,</sup><xref ref-type="bibr" rid="B33">33</xref> Portanto, o objetivo do presente trabalho &#233; estudar as complica&#231;&#245;es relacionadas &#224; EEF e as vari&#225;veis cl&#237;nicas e ecocardiogr&#225;ficas preditoras dessas ocorr&#234;ncias.</p>
      </sec>
      <sec sec-type="methods">
        <title>M&#233;todos</title>
        <p>Trata-se de um estudo transversal anal&#237;tico e descritivo realizado entre janeiro de 2000 e junho de 2014.</p>
        <sec>
          <title>Pacientes</title>
          <p>A amostra, por conveni&#234;ncia, consistiu de 10250 pacientes com DAC suspeita e/ou estabelecida submetidos &#224; ecocardiografia sob estresse pelo esfor&#231;o f&#237;sico no Laborat&#243;rio de Ecocardiografia da Cl&#237;nica e Hospital S&#227;o Lucas (ECOLAB), Aracaju-SE. Foram inclu&#237;dos todos os pacientes acima de 25 anos referendados e encaminhados ao servi&#231;o segundo a indica&#231;&#227;o dos m&#233;dicos assistentes, &#224; exce&#231;&#227;o, apenas, daqueles que se recusaram a participar do estudo. As indica&#231;&#245;es para a realiza&#231;&#227;o do exame foram: pr&#233;-operat&#243;rio, precordialgia t&#237;pica ou at&#237;pica, estratifica&#231;&#227;o de risco, TE positivo ou negativo com cl&#237;nica, TE ineficaz, check-up.</p>
          <p>Os pacientes foram divididos em dois grupos, de acordo com a ocorr&#234;ncia das complica&#231;&#245;es mais frequentemente observadas &#224; EEF: grupo G1 - composto por pacientes que apresentaram tais complica&#231;&#245;es ao exame e grupo G2 - formado por indiv&#237;duos que n&#227;o as exibiram.</p>
        </sec>
        <sec>
          <title>Caracter&#237;sticas cl&#237;nicas</title>
          <p>Os dados cl&#237;nicos foram colhidos e registrados por meio de entrevistas realizadas antes do procedimento. Foi utilizado um question&#225;rio estruturado que investigava peso, altura, sintomas como dispneia e dor tor&#225;cica, medica&#231;&#245;es, fatores de risco para DAC e hist&#243;rico de cardiopatia familiar ou pessoal. Assim como dados referente a DAC pr&#233;via como infarto agudo do mioc&#225;rdio, revasculariza&#231;&#227;o percut&#226;nea e cir&#250;rgica. Ademais, os resultados de exames laboratoriais e exames do aparelho cardiovascular pr&#233;vios foram registrados.</p>
          <p>Caracterizou-se obesidade um &#237;ndice de massa corp&#243;rea maior que 30 kg/m<sup>2</sup>. Definiu-se hipercolesterolemia como n&#237;vel s&#233;rico de colesterol total superior a 200 mg/dL (ap&#243;s jejum de 12 horas) e hipertrigliceridemia como n&#237;vel s&#233;rico de triglic&#233;rides superior a 150 mg/dL (ap&#243;s jejum de 12 horas) ou uso de agente antilip&#234;mico (estatinas e/ou fibratos).</p>
          <p>Considerou-se hipertens&#227;o arterial sist&#234;mica quando os n&#237;veis press&#243;ricos aferidos no membro superior, em repouso, eram press&#227;o arterial sist&#243;lica &#8805; 140 mmHg e/ou diast&#243;lica &#8805; 90 mmHg, ou quando faziam uso de medica&#231;&#227;o anti-hipertensiva.</p>
          <p>O diabetes melito foi definido pela presen&#231;a de glicemia em jejum acima de 126 mg/dL ou pelo uso de insulina ou agentes hipoglicemiantes orais.</p>
          <p>Definiu-se infarto do mioc&#225;rdio antigo por meio de hist&#243;ria cl&#237;nica e/ou exames complementares pr&#233;vios, como ECG, ecocardiograma e/ou cineangiocoronariografia.</p>
        </sec>
        <sec>
          <title>Teste ergom&#233;trico</title>
          <p>Primeiramente, o protocolo consistiu na realiza&#231;&#227;o de ECG de doze deriva&#231;&#245;es e ecocardiograma de repouso ap&#243;s a investiga&#231;&#227;o cl&#237;nica. Em seguida, realizou-se o esfor&#231;o f&#237;sico em esteira rolante e, logo ap&#243;s, procedeu-se novamente a aquisi&#231;&#227;o das imagens ecocardiogr&#225;ficas.</p>
          <p>Todos os pacientes foram submetidos aos protocolos padr&#227;o de Bruce ou Ellestad durante o teste ergom&#233;trico. Foi realizada monitora&#231;&#227;o cont&#237;nua da frequ&#234;ncia card&#237;aca, e os pacientes encorajados a alcan&#231;ar o seu pico m&#225;ximo de esfor&#231;o f&#237;sico. Para c&#225;lculos metab&#243;licos, o volume de oxig&#234;nio inspirado no pico do exerc&#237;cio (VO<sub>2</sub>max) foi obtido indiretamente por meio da seguinte f&#243;rmula: VO<sub>2</sub> max = 14,76 - 1,379t + 0,451t<sup>2</sup> - 0,012t<sup>3</sup>, em que t &#233; a dura&#231;&#227;o do teste<xref ref-type="bibr" rid="B34">34</xref> em minutos. A carga foi expressa em equivalentes metab&#243;licos, em que 1 MET corresponde a 3,5 mL/kg&#183;min de VO<sub>2</sub> inspirado, referente ao repouso.<xref ref-type="bibr" rid="B35">35</xref> Durante o teste, os indiv&#237;duos foram continuamente monitorados com ECG de tr&#234;s deriva&#231;&#245;es.</p>
          <p>Foram denominadas altera&#231;&#245;es eletrocardiogr&#225;ficas isqu&#234;micas ao exerc&#237;cio a ocorr&#234;ncia de infradesnivelamento do segmento ST horizontal ou descendente &#8805; 1 mm para homens e &#8805; 1,5 mm para mulheres a 0,08 segundos do ponto J.<xref ref-type="bibr" rid="B8">8</xref>
					</p>
        </sec>
        <sec>
          <title>Ecocardiografia sob estresse f&#237;sico</title>
          <p>O ambiente para a realiza&#231;&#227;o do exame &#233; ergonomicamente projetado com equipe constantemente treinada, por se tratar de Hospital considerado refer&#234;ncia em cardiologia e possuidor de acredita&#231;&#227;o n&#237;vel 3 por avalia&#231;&#227;o espec&#237;fica. Como rotina, &#233; recomendada a suspens&#227;o de betabloqueadores tr&#234;s dias antes do exame, mantendo-se as demais drogas usuais do paciente.</p>
          <p>Exames foram realizados com equipamento Hewlett Packard/Phillips SONOS 5500 at&#233; o ano de 2012 e em seguida com o Phillips IE-33, observando-se os aspectos t&#233;cnicos classicamente descritos por Schiller et al.<xref ref-type="bibr" rid="B36">36</xref> As imagens ecocardiogr&#225;ficas bidimensionais foram obtidas nas janelas ac&#250;sticas paraesternais e apicais, durante o repouso e imediatamente ap&#243;s o esfor&#231;o, com o paciente em dec&#250;bito lateral esquerdo e registro eletrocardiogr&#225;fico simult&#226;neo.</p>
          <p>A motilidade segmentar da parede do ventr&#237;culo esquerdo (VE) foi avaliada por ecocardiografista experiente, com n&#237;vel III, conforme preconizado pela Sociedade Americana de Ecocardiografia. O espessamento parietal segmentar do VE foi avaliado quantitativamente no repouso e, ap&#243;s o esfor&#231;o, por meio da utiliza&#231;&#227;o do modelo de 16 segmentos, graduado em: 1, normal; 2, hipocin&#233;tico; 3, acin&#233;tico; 4, discin&#233;tico. O &#237;ndice de escore da motilidade do ventr&#237;culo esquerdo (IEMVE) foi calculado no repouso e durante o exerc&#237;cio como a soma dos escores conferidos a cada um dos 16 segmentos dividido pelo n&#250;mero de segmentos avaliados no dado momento. O IEMVE igual a um corresponde &#224; normalidade, de 1,1 a 1,6 representa disfun&#231;&#227;o leve, de 1,61 a 2, disfun&#231;&#227;o moderada. Valores maiores que 2 representam disfun&#231;&#227;o importante.<xref ref-type="bibr" rid="B36">36</xref> A diferen&#231;a entre o IEMVE de esfor&#231;o e de repouso &#233; chamada de &#916;IEMVE. O desenvolvimento de nova altera&#231;&#227;o na motilidade parietal ou piora de dissinergia existente (&#916;IEMVE &#8800; 0) foi considerado indicativo de isquemia mioc&#225;rdica.</p>
        </sec>
        <sec>
          <title>An&#225;lise da ocorr&#234;ncia de complica&#231;&#245;es</title>
          <p>Os pacientes foram observados antes, durante e ap&#243;s o estresse sob esfor&#231;o f&#237;sico para verifica&#231;&#227;o de poss&#237;veis complica&#231;&#245;es decorrentes dele, sendo monitorados com o ECG de doze deriva&#231;&#245;es durante esse tempo. As complica&#231;&#245;es pesquisadas e suas respectivas defini&#231;&#245;es s&#227;o baseadas naquelas descritas por Geleijnse et al.<xref ref-type="bibr" rid="B29">29</xref>
					</p>
          <p>Foram consideradas complica&#231;&#245;es maiores, a presen&#231;a de morte, infarto agudo do mioc&#225;rdio, ruptura card&#237;aca, fibrila&#231;&#227;o ventricular e assistolia card&#237;aca.</p>
          <p>As complica&#231;&#245;es menores foram definidas como bloqueio atrioventricular (BAV), espasmo coron&#225;rio, acidente vascular encef&#225;lico (AVE), hipotens&#227;o e hipertens&#227;o arterial no pico do esfor&#231;o, taquicardia ventricular sustentada (&gt; 30 batimentos/min), taquicardia ventricular n&#227;o sustentada, taquicardia supraventricular sustentada, taquicardia supraventricular n&#227;o sustentada, extrass&#237;stoles ventriculares e extrass&#237;stoles supraventriculares</p>
        </sec>
        <sec>
          <title>An&#225;lise estat&#237;stica</title>
          <p>As vari&#225;veis categ&#243;ricas foram apresentadas como porcentagens e analisadas por meio do teste de qui-quadrado (<italic>&#967;</italic><sup>2</sup>) ou teste exato de Fisher. As vari&#225;veis cont&#237;nuas foram representadas por m&#233;dia +/- desvio padr&#227;o e comparadas com aux&#237;lio do teste <italic>t</italic> n&#227;o pareado de Student ou teste de Mann-Whitney U, conforme apropriado.</p>
          <p>Para avaliar os fatores de risco preditores de complica&#231;&#245;es &#224; EEF foi utilizada regress&#227;o de Cox de forma univariada e multivariada. As vari&#225;veis inclu&#237;das no modelo multivariado foram todas aquelas com p &lt; 0,1 na an&#225;lise univariada. Problemas de multicolinearilidade foram resolvidos antes da inser&#231;&#227;o das vari&#225;ves no modelo. Foi utilizado o m&#233;todo forward de sele&#231;&#227;o de vari&#225;veis. As vari&#225;veis que permaneceram no modelo foram testadas em busca de poss&#237;veis intera&#231;&#245;es. O pressuposto de proporcionalidade de risco foi testado por meio dos res&#237;duos de Schoenfeld para cada uma das vari&#225;veis que permaneceram no modelo final. Foram considerados significativos os valores de p &lt; 0,05. As an&#225;lises estat&#237;sticas foram processadas por meio do programa <italic>Statistical Package for the Social Sciences</italic> (<italic>SPSS</italic>) vers&#227;o 21.0 (Chicago, IL).</p>
        </sec>
        <sec>
          <title>Aspectos &#233;ticos</title>
          <p>Os princ&#237;pios &#233;ticos que regem a experimenta&#231;&#227;o humana foram cuidadosamente seguidos, e todos os pacientes assinaram termo de consentimento livre e esclarecido. O estudo foi aprovado pelo Comit&#234; de &#201;tica em Pesquisa da Universidade Federal de Sergipe (CAAE 1818.0.000.107-06).</p>
        </sec>
      </sec>
      <sec sec-type="results">
        <title>Resultados</title>
        <p>Foram estudados 10250 pacientes, 4936 (48,2%) do sexo masculino, com m&#233;dia de idade de 57,19 &#177; 11,24 anos, com idades lim&#237;trofes 25 e 93 anos. N&#227;o houve registro de complica&#231;&#245;es maiores como morte, infarto agudo do mioc&#225;rdio, ruptura card&#237;aca, fibrila&#231;&#227;o ventricular e assistolia card&#237;aca.</p>
        <p>As arritmias card&#237;acas foram as complica&#231;&#245;es mais frequentemente encontradas durante o exame, com isso, a distribui&#231;&#227;o por grupos foi a seguinte: 2843 pacientes no grupo G1 (27,7%) e 7407 indiv&#237;duos no grupo G2 (72,3%).</p>
        <p>Houve um caso para cada uma das seguintes complica&#231;&#245;es: BAV, espasmo coron&#225;rio, AVE e hipotens&#227;o arterial, representando 0,009% da amostra. Hipertens&#227;o arterial no pico do esfor&#231;o foi observada em 1011 indiv&#237;duos, totalizando 9,9% da popula&#231;&#227;o, sendo que desses, 82% apresentavam, previamente ao exame, hipertens&#227;o arterial sist&#234;mica (HAS).</p>
        <p>As complica&#231;&#245;es mais frequentemente observadas nesse estudo foram as arritmias card&#237;acas. Os ritmos observados foram as taquicardias ventriculares e supraventriculares n&#227;o-sustentadas e as extrass&#237;stoles ventriculares e supraventriculares, sejam estas isoladas, em salva, bigeminadas, monom&#243;rficas ou polim&#243;rficas. A frequ&#234;ncia delas est&#225; descrita na <xref ref-type="table" rid="t5">Tabela 1</xref>. Em todos os casos, foram revertidas com a interrup&#231;&#227;o do esfor&#231;o f&#237;sico, assim como com o uso de dinitrato de isossorbida e oxig&#234;nio inalat&#243;rio quando na presen&#231;a de isquemia mioc&#225;rdica associada, sem repercuss&#245;es hemodin&#226;micas que necessitassem interna&#231;&#227;o em unidade de terapia intensiva, uma vez que n&#227;o foram registradas fibrila&#231;&#227;o ventricular ou taquicardia ventricular sustentada.</p>
        <table-wrap id="t5">
          <label>Tabela 1</label>
          <caption>
            <title>Frequ&#234;ncia de arritmias card&#237;acas &#224; EEF</title>
          </caption>
          <table frame="hsides" rules="groups">
            <colgroup width="50%">
              <col/>
              <col/>
            </colgroup>
            <thead>
              <tr>
                <th align="left">Arritmia card&#237;aca</th>
                <th align="center">Frequ&#234;ncia<break/>n = 10250</th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td align="left">Taquicardia ventricular sustentada</td>
                <td align="center">0 (0%)</td>
              </tr>
              <tr>
                <td align="left">Taquicardia ventricular n&#227;o sustentada</td>
                <td align="center">114 (1,1%)</td>
              </tr>
              <tr>
                <td align="left">Taquicardia supraventricular sustentada</td>
                <td align="center">0 (0%)</td>
              </tr>
              <tr>
                <td align="left">Taquicardia supraventricular n&#227;o sustentada</td>
                <td align="center">645 (6,2%)</td>
              </tr>
              <tr>
                <td align="left">Extrass&#237;stoles ventriculares</td>
                <td align="center">1186 (11,5%)</td>
              </tr>
              <tr>
                <td align="left">Extrass&#237;stoles supraventriculares</td>
                <td align="center">1418 (13,7%)</td>
              </tr>
            </tbody>
          </table>
          <table-wrap-foot>
            <fn id="TFN05">
              <p>EEF: ecocardiografia sob estresse f&#237;sico.</p>
            </fn>
          </table-wrap-foot>
        </table-wrap>
        <p>Dividiu-se, portanto, os 10250 pacientes em dois grupos: o grupo G1- composto por 2843 (27,7%) pacientes que apresentaram arritmias card&#237;acas ao exame e o grupo G2 - composto por 7407 (72,3%) pacientes com aus&#234;ncia de arritmias.</p>
        <sec>
          <title>Caracter&#237;sticas cl&#237;nicas dos grupos</title>
          <p>O grupo G1 apresentou maior idade m&#233;dia, maior frequ&#234;ncia de HAS e tabagismo. Com rela&#231;&#227;o ao g&#234;nero e demais comorbidades associadas, ambos os grupos apresentaram frequ&#234;ncias similares (<xref ref-type="table" rid="t6">Tabela 2</xref>).</p>
          <table-wrap id="t6">
            <label>Tabela 2</label>
            <caption>
              <title>Caracter&#237;sticas cl&#237;nicas dos pacientes que apresentaram (G1) ou n&#227;o (G2) arritmias card&#237;acas &#224; EEF</title>
            </caption>
            <table frame="hsides" rules="groups">
              <colgroup width="25%">
                <col/>
                <col/>
                <col/>
                <col/>
              </colgroup>
              <thead>
                <tr>
                  <th align="left">Caracter&#237;sticas cl&#237;nicas</th>
                  <th align="center">G1<break/>n = 2843 (27,7%)</th>
                  <th align="center">G2<break/>n = 7407 (72,2%)</th>
                  <th align="center">p</th>
                </tr>
              </thead>
              <tbody>
                <tr>
                  <td align="left">Sexo masculino</td>
                  <td align="center">1410 (49,6%)</td>
                  <td align="center">3525 (47,6%)</td>
                  <td align="center">0,06</td>
                </tr>
                <tr>
                  <td align="left">Idade (m&#233;dia em anos)</td>
                  <td align="center">60,81 &#177; 10,78</td>
                  <td align="center">55,79 &#177; 11,1</td>
                  <td align="center">&lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left">IMC (kg/m<sup>2</sup>)</td>
                  <td align="center">27,2 &#177; 4,28</td>
                  <td align="center">27,3 &#177; 4,43</td>
                  <td align="center">0,3</td>
                </tr>
                <tr>
                  <td align="left">HAS</td>
                  <td align="center">1828 (64,3%)</td>
                  <td align="center">4251 (57,4%)</td>
                  <td align="center">&lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left">Diabetes Mellitus</td>
                  <td align="center">102 (3,6%)</td>
                  <td align="center">637 (8,6%)</td>
                  <td align="center">0,12</td>
                </tr>
                <tr>
                  <td align="left">Dislipidemia</td>
                  <td align="center">1709 (60,1%)</td>
                  <td align="center">4370 (59%)</td>
                  <td align="center">0,33</td>
                </tr>
                <tr>
                  <td align="left">Tabagismo</td>
                  <td align="center">114 (4%)</td>
                  <td align="center">378 (5,1%)</td>
                  <td align="center">0,02</td>
                </tr>
                <tr>
                  <td align="left">Antecedentes familiares de cardiopatia</td>
                  <td align="center">1595 (56,1%)</td>
                  <td align="center">4163 (56,2%)</td>
                  <td align="center">0,92</td>
                </tr>
                <tr>
                  <td align="left">Dispneia</td>
                  <td align="center">264 (9,3%)</td>
                  <td align="center">555 (7,5%)</td>
                  <td align="center">0,003</td>
                </tr>
                <tr>
                  <td align="left">Precordialgia</td>
                  <td align="center">816 (28,7%)</td>
                  <td align="center">2326 (31,4%)</td>
                  <td align="center">0,191</td>
                </tr>
                <tr>
                  <td align="left">IAM pr&#233;vio</td>
                  <td align="center">165 (5,8%)</td>
                  <td align="center">318 (4,3%)</td>
                  <td align="center">0,002</td>
                </tr>
                <tr>
                  <td align="left">Angioplastia</td>
                  <td align="center">213 (7,5%)</td>
                  <td align="center">533 (7,2%)</td>
                  <td align="center">0,639</td>
                </tr>
                <tr>
                  <td align="left">Revasculariza&#231;&#227;o mioc&#225;rdica</td>
                  <td align="center">205 (7,2%)</td>
                  <td align="center">385 (5,2%)</td>
                  <td align="center">&lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left">Betabloqueador</td>
                  <td align="center">690 (24,3%)</td>
                  <td align="center">1555 (21,0%)</td>
                  <td align="center">&lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left">Bloqueador de canal de c&#225;lcio</td>
                  <td align="center">239 (8,4%)</td>
                  <td align="center">481 (6,5%)</td>
                  <td align="center">0,001</td>
                </tr>
                <tr>
                  <td align="left">IECA</td>
                  <td align="center">318 (11,2%)</td>
                  <td align="center">674 (9,1%)</td>
                  <td align="center">0,001</td>
                </tr>
                <tr>
                  <td align="left">BRA</td>
                  <td align="center">424 (14,9%)</td>
                  <td align="center">1059 (14,3%)</td>
                  <td align="center">0,468</td>
                </tr>
                <tr>
                  <td align="left">Estatina</td>
                  <td align="center">640 (22,5%)</td>
                  <td align="center">1504 (20,3%)</td>
                  <td align="center">0,016</td>
                </tr>
                <tr>
                  <td align="left">Glicemia</td>
                  <td align="center">100,03 &#177; 25,26</td>
                  <td align="center">99,72 &#177; 29,23</td>
                  <td align="center">0,907</td>
                </tr>
                <tr>
                  <td align="left">Colesterol total (mg/dL)</td>
                  <td align="center">196,86 &#177; 47,81</td>
                  <td align="center">192,88 &#177; 46,28</td>
                  <td align="center">0,364</td>
                </tr>
                <tr>
                  <td align="left">HDL (mg/dL)</td>
                  <td align="center">49,95 &#177; 13,97</td>
                  <td align="center">46,54 &#177; 13,33</td>
                  <td align="center">0,748</td>
                </tr>
                <tr>
                  <td align="left">LDL (mg/dL)</td>
                  <td align="center">123,28 &#177; 42,16</td>
                  <td align="center">116,87 &#177; 41,28</td>
                  <td align="center">0,115</td>
                </tr>
                <tr>
                  <td align="left">Triglic&#233;rides (mg/dL)</td>
                  <td align="center">148,95 &#177; 89,06</td>
                  <td align="center">154,78 &#177; 100,74</td>
                  <td align="center">0,535</td>
                </tr>
              </tbody>
            </table>
            <table-wrap-foot>
              <fn id="TFN06">
                <p>IMC: &#237;ndice de massa corp&#243;rea; HAS: hipertens&#227;o arterial sist&#234;mica; IAM: infarto agudo do mioc&#225;rdio; IECA: inibidor da enzima conversora de angiotensina; BRA: bloqueador de receptor da angiotensina; HDL-C: colesterol de alta densidade; LDL-C: colesterol de baixa densidade.</p>
              </fn>
            </table-wrap-foot>
          </table-wrap>
        </sec>
        <sec>
          <title>Caracter&#237;sticas ecocardiogr&#225;ficas dos grupos</title>
          <p>&#192; ecodopplercardiografia transtor&#225;cica, houve diferen&#231;a significativa nos di&#226;metros da aorta, &#225;trio esquerdo, espessura e massa do VE. A fra&#231;&#227;o de eje&#231;&#227;o do VE esteve preservada em ambos os grupos, encontrando-se mais baixa nos pacientes do grupo G1 (<xref ref-type="table" rid="t7">Tabela 3</xref>).</p>
          <table-wrap id="t7">
            <label>Tabela 3</label>
            <caption>
              <title>Caracter&#237;sticas ecocardiogr&#225;ficas dos pacientes que apresentaram (G1) ou n&#227;o (G2) arritmias card&#237;acas &#224; EEF</title>
            </caption>
            <table frame="hsides" rules="groups">
              <colgroup>
                <col width="1%"/>
                <col width="24%"/>
                <col width="24%"/>
                <col width="24%"/>
                <col width="24%"/>
              </colgroup>
              <thead>
                <tr>
                  <th align="left" colspan="2">Caracter&#237;sticas ecocardiogr&#225;ficas</th>
                  <th align="center">G1<break/>n = 2843 (27,7%)</th>
                  <th align="center">G2<break/>n = 7407 (72,3%)</th>
                  <th align="center">p</th>
                </tr>
              </thead>
              <tbody>
                <tr>
                  <td align="left" colspan="2">Aorta (cm)</td>
                  <td align="center">3,23 &#177; 0,39</td>
                  <td align="center">3,17 &#177; 0,4</td>
                  <td align="center">&lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left" colspan="2">AE (cm)</td>
                  <td align="center">3,87 &#177; 0,47</td>
                  <td align="center">3,76 &#177; 0,43</td>
                  <td align="center">&lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left" colspan="2">Volume do AE (ml/m<sup>2</sup>)</td>
                  <td align="center">24,26 &#177; 24,25</td>
                  <td align="center">22,52 &#177; 26,02</td>
                  <td align="center">0,11</td>
                </tr>
                <tr>
                  <td align="left" colspan="2">Rela&#231;&#227;o E/e&#180;</td>
                  <td align="center">9,94 &#177; 3,4</td>
                  <td align="center">9,41 &#177; 3,36</td>
                  <td align="center">0,005</td>
                </tr>
                <tr>
                  <td align="left" colspan="2">&#205;ndice de massa de VE (g/m<sup>2</sup>)</td>
                  <td align="center">95,2 &#177; 87,74</td>
                  <td align="center">97,9 &#177; 62,88</td>
                  <td align="center">&lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left" colspan="2">Espessura relativa da parede de VE</td>
                  <td align="center">31,9 &#177; 5,42</td>
                  <td align="center">32,3 &#177; 6,77</td>
                  <td align="center">0,005</td>
                </tr>
                <tr>
                  <td align="left" colspan="2">Fra&#231;&#227;o de eje&#231;&#227;o (%)</td>
                  <td align="center">0,66 &#177; 0,06</td>
                  <td align="center">0,67 &#177; 0,06</td>
                  <td align="center">&lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left" colspan="2">IEMVE em repouso</td>
                  <td align="center">1,039 &#177; 0,141</td>
                  <td align="center">1,022 &#177; 0,104</td>
                  <td align="center">&lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left" colspan="2">IEMVE ao esfor&#231;o</td>
                  <td align="center">1,056 &#177; 0,153</td>
                  <td align="center">1,035 &#177; 0,117</td>
                  <td align="center">&lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left" colspan="5"><bold>Resultado da EEF</bold> &lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left">
									</td>
                  <td align="left">&#8211; Normal</td>
                  <td align="center">71,4%</td>
                  <td align="center">78,8%</td>
                  <td align="center" rowspan="4">&lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left">
									</td>
                  <td align="left">&#8211; Isqu&#234;mico</td>
                  <td align="center">12,8%</td>
                  <td align="center">10%</td>
                </tr>
                <tr>
                  <td align="left">
									</td>
                  <td align="left">&#8211; Isquemia fixa</td>
                  <td align="center">10,9%</td>
                  <td align="center">8,7%</td>
                </tr>
                <tr>
                  <td align="left">
									</td>
                  <td align="left">&#8211; Isquemia fixa e induzida</td>
                  <td align="center">4,9%</td>
                  <td align="center">2,4%</td>
                </tr>
              </tbody>
            </table>
            <table-wrap-foot>
              <fn id="TFN07">
                <p>AE: &#225;trio esquerdo; VE: ventr&#237;culo esquerdo; IEMVE: &#237;ndice de escore e motilidade ventricular esquerda; EEF: ecocardiografia sob estresse f&#237;sico.</p>
              </fn>
            </table-wrap-foot>
          </table-wrap>
          <p>&#192; EEF, foi observada diferen&#231;a no &#237;ndice de escore de motilidade do VE tanto em repouso quanto no esfor&#231;o. Observou-se, mais frequentemente, presen&#231;a de isquemia mioc&#225;rdica no grupo G1.</p>
        </sec>
        <sec>
          <title>An&#225;lise de regress&#227;o log&#237;stica</title>
          <p>Ao realizar-se teste para contemplar os poss&#237;veis fatores de confus&#227;o no modelo, apenas duas vari&#225;veis estiveram independentemente associadas &#224; ocorr&#234;ncia de complica&#231;&#245;es. N&#227;o houve intera&#231;&#245;es entre as vari&#225;veis analisadas (<xref ref-type="table" rid="t8">Tabela 4</xref>).</p>
          <table-wrap id="t8">
            <label>Tabela 4</label>
            <caption>
              <title>Regress&#227;o log&#237;stica multivariada com par&#226;metros associados &#224; presen&#231;a de arritmias card&#237;acas &#224; EEF</title>
            </caption>
            <table frame="hsides" rules="groups">
              <colgroup width="25%">
                <col/>
                <col/>
                <col/>
                <col/>
              </colgroup>
              <thead>
                <tr>
                  <th align="left">Vari&#225;vel</th>
                  <th align="center">Odds Ratio</th>
                  <th align="center">IC 95%</th>
                  <th align="center">p</th>
                </tr>
              </thead>
              <tbody>
                <tr>
                  <td align="left">Idade</td>
                  <td align="center">1,04</td>
                  <td align="center">1,038 &#8211; 1,049</td>
                  <td align="center">&lt; 0,001</td>
                </tr>
                <tr>
                  <td align="left">&#193;trio esquerdo</td>
                  <td align="center">1,64</td>
                  <td align="center">1,448 &#8211; 1,872</td>
                  <td align="center">&lt; 0,001</td>
                </tr>
              </tbody>
            </table>
            <table-wrap-foot>
              <fn id="TFN08">
                <p>IC: intervalo de confian&#231;a; AE: &#225;trio esquerdo; EEF: ecocardiografia sob estresse f&#237;sico.</p>
              </fn>
            </table-wrap-foot>
          </table-wrap>
        </sec>
      </sec>
      <sec sec-type="discussion">
        <title>Discuss&#227;o</title>
        <p>A EEF mostrou-se segura neste estudo, com baixa frequ&#234;ncia de complica&#231;&#245;es, nenhuma delas apresentando desfecho fatal. &#211;bito &#224; EE &#233; observado com mais frequ&#234;ncia ao estresse farmacol&#243;gico.<xref ref-type="bibr" rid="B29">29</xref> Pode ser que esse fato ocorra devido ao pr&#243;prio mecanismo por interm&#233;dio do qual as drogas estressoras atuam no cora&#231;&#227;o: a dobutamina o faz estimulando receptores adren&#233;rgicos, aumentando cronotropismo e inotropismo e possuindo tamb&#233;m grande potencial arritmog&#234;nico e hipertensor; o dipiridamol estressa o m&#250;sculo card&#237;aco ao estimular receptores de adenosina e reduzir o fluxo subendoc&#225;rdico, apresenta tamb&#233;m um efeito cronotr&#243;pico e dromotr&#243;pico negativo, al&#233;m de atividade broncoconstritora. O exerc&#237;cio f&#237;sico, no entanto, representa uma modalidade mais fisiol&#243;gica de estresse, sem apresentar os efeitos colaterais acima descritos.<xref ref-type="bibr" rid="B18">18</xref> H&#225; ainda um vi&#233;s de sele&#231;&#227;o: os candidatos eleg&#237;veis ao teste por esfor&#231;o f&#237;sico apresentam-se com fra&#231;&#227;o de eje&#231;&#227;o preservada, enquanto aqueles do estresse farmacol&#243;gico podem encontrar-se em est&#225;gios mais avan&#231;ados de cardiopatia.</p>
        <p>Em grande estudo multic&#234;ntrico com 85997 pacientes submetidos &#224; EE, 26295 havendo realizado o estresse f&#237;sico e o restante, o farmacol&#243;gico, n&#227;o houve nenhum desfecho fatal no grupo submetido &#224; EEF, enquanto no grupo submetido ao estresse por drogas houve 5 &#243;bitos. Quanto &#224; frequ&#234;ncia de eventos amea&#231;adores &#224; vida, a propor&#231;&#227;o desses &#224; EEF foi de 1 em 6574 casos, ao passo que com o dipiridamol e a dobutamina observou-se 1 a cada 1294 e 1 a cada 557 casos, respectivamente.<xref ref-type="bibr" rid="B32">32</xref>
				</p>
        <p>Em estudo marroquino com 311 pacientes, sendo 206 submetidos &#224; EEF, tamb&#233;m n&#227;o foi registrado nenhum evento maior ou fatal.<xref ref-type="bibr" rid="B33">33</xref> Segundo Sicari et al.<xref ref-type="bibr" rid="B18">18</xref> no estresse farmacol&#243;gico com a dobutamina, ocorrem s&#233;rias complica&#231;&#245;es em 3 de cada 1.000 pacientes e com o dipiridamol em 1 de cada 1.000 pacientes. J&#225; na EEF, tais complica&#231;&#245;es ocorrem em 1 de cada 10.000 pacientes.</p>
        <p>No tocante &#224;s complica&#231;&#245;es menores, as mais frequentes foram as arritmias, principalmente as de menor repercuss&#227;o hemodin&#226;mica e facilmente revers&#237;veis com a cessa&#231;&#227;o do esfor&#231;o, como as extrass&#237;stoles supraventriculares e ventriculares, sendo este achado de acordo com um estudo<xref ref-type="bibr" rid="B33">33</xref> e n&#227;o mencionado por outros estudos de maior porte.<xref ref-type="bibr" rid="B29">29</xref><sup>,</sup><xref ref-type="bibr" rid="B32">32</xref>
				</p>
        <p>A presen&#231;a de hipertens&#227;o arterial ao esfor&#231;o foi observada em uma porcentagem significativa da amostra (9,9% dos casos), em indiv&#237;duos em sua maioria hipertensos cr&#244;nicos. Uma das raz&#245;es para essa marcada descompensa&#231;&#227;o da resposta press&#243;rica ao estresse pode ser o protocolo de preparo para o exame de nossa institui&#231;&#227;o que inclu&#237;a suspens&#227;o de beta-bloqueadores por 3 dias antes desse. Houve uma relevante diferen&#231;a quanto a achados da literatura, fato que tamb&#233;m pode ser devido &#224; maioria dos trabalhos se utilizarem do estresse farmacol&#243;gico, que pode ter como resposta, em at&#233; 7,6% dos casos,<xref ref-type="bibr" rid="B29">29</xref><sup>,</sup><xref ref-type="bibr" rid="B32">32</xref> hipotens&#227;o severa e choque cardiog&#234;nico.</p>
        <p>Quanto ao perfil cl&#237;nico-demogr&#225;fico da amostra, somente Fennich et al.<xref ref-type="bibr" rid="B33">33</xref> as menciona. Neste estudo, a idade foi semelhante a do presente trabalho (59,2 anos), por&#233;m houve uma maior preval&#234;ncia de diabetes mellitus e tabagismo e uma menor de HAS, diferentemente dos nossos achados.</p>
        <p>As vari&#225;veis ditas preditoras independentes, &#225;trio esquerdo e idade apresentam uma rela&#231;&#227;o &#237;ntima entre si. Alguns estudos reportaram que o tamanho do AE naturalmente aumentaria com a idade.<xref ref-type="bibr" rid="B37">37</xref><sup>-</sup><xref ref-type="bibr" rid="B39">39</xref> Desse modo, a senesc&#234;ncia proporcionaria altera&#231;&#245;es que culminariam com a dilata&#231;&#227;o e a disfun&#231;&#227;o do AE, aumentando, assim, a predisposi&#231;&#227;o para arritmias atriais,<xref ref-type="bibr" rid="B39">39</xref> o que pode, inclusive, influenciar a ocorr&#234;ncia dessas quando o paciente &#233; submetido ao estresse, como na EEF. Ainda tratando-se da idade, &#233; importante esse achado como preditor independente da ocorr&#234;ncia de complica&#231;&#245;es &#224; EEF, j&#225; que este &#233; um fato corriqueiramente observado na pr&#225;tica cl&#237;nica, por&#233;m ainda n&#227;o descrito na literatura em rela&#231;&#227;o ao esfor&#231;o f&#237;sico.</p>
        <p>Uma outra lacuna na literatura diz respeito &#224; rela&#231;&#227;o entre vari&#225;veis ecocardiogr&#225;ficas e a ocorr&#234;ncia de complica&#231;&#245;es &#224; EEF, visto que nosso trabalho encontrou diversas diferen&#231;as significativas e n&#227;o existem ainda estudos sobre as mesmas. Outra relevante observa&#231;&#227;o &#233; a de uma diferen&#231;a extremamente significativa na presen&#231;a de isquemia mioc&#225;rdica em pacientes que desenvolveram eventos adversos &#224; EEF, podendo isso ocorrer devido &#224; doen&#231;a arterial coron&#225;ria que altera o sistema de condu&#231;&#227;o el&#233;trico card&#237;aco e induz a presen&#231;a de arritmias, fato esse bastante estudado no estresse farmacol&#243;gico, a exemplo do trabalho de Abreu et al.<xref ref-type="bibr" rid="B40">40</xref> mas ainda sem evid&#234;ncias &#224; EEF.</p>
        <p>Apesar de as diretrizes vigentes<xref ref-type="bibr" rid="B41">41</xref> recomendarem a utiliza&#231;&#227;o dessa metodologia em pacientes de risco intermedi&#225;rio, na pr&#225;tica cl&#237;nica, muitas vezes nos deparamos com a realiza&#231;&#227;o em pacientes de alto risco. Todavia, mesmo em tais pacientes desse grupo, n&#227;o logramos complica&#231;&#245;es identific&#225;veis.</p>
        <p>Portanto, este trabalho mostra dados interessantes ainda pouco estudados no campo da EEF, uma metodologia que vem ganhando mais espa&#231;o nos &#250;ltimos anos, por sua versatilidade, reprodutibilidade e custo-efetividade, sendo corroborada pela baixa frequ&#234;ncia de eventos adversos. Com isso, espera-se que advenham novos estudos em busca de mais conhecimentos sobre o tema.</p>
        <p>Com refer&#234;ncia &#224;s limita&#231;&#245;es do estudo, cabe destacar aquelas inerentes a qualquer estudo observacional, nos quais vari&#225;veis n&#227;o mensuradas podem corroborar a diferen&#231;a estat&#237;stica entre os grupos. Tamb&#233;m existe nesta amostra, o vi&#233;s de pr&#233;-sele&#231;&#227;o, j&#225; que os pacientes submetidos &#224; EEF apresentam cardiopatias de base ou fatores de risco para o desenvolvimento das mesmas.</p>
      </sec>
      <sec sec-type="conclusions">
        <title>Conclus&#227;o</title>
        <p>A EEF mostra-se uma modalidade segura de estresse, n&#227;o sendo observada no presente estudo a presen&#231;a de complica&#231;&#245;es que representem risco de morte. Os eventos adversos ocorridos foram de menor porte, sendo facilmente revertidos com a cessa&#231;&#227;o do esfor&#231;o f&#237;sico. A seguran&#231;a e exequibilidade dessa modalidade de estresse, associadas &#224; sua importante validade diagn&#243;stica e progn&#243;stica, justificam seu uso na pr&#225;tica cl&#237;nica.</p>
      </sec>
    </body>
    <back>
      <fn-group>
        <fn fn-type="financial-disclosure">
          <p>
            <bold>Fontes de Financiamento</bold>
          </p>
          <p>O presente estudo n&#227;o teve fontes de financiamento externas.</p>
        </fn>
        <fn fn-type="other">
          <p>
            <bold>Vincula&#231;&#227;o Acad&#234;mica</bold>
          </p>
          <p>Este artigo &#233; parte de tese de Doutorado de Carlos Jos&#233; Oliveira de Matos e Igor Larchert Mota pela Universidade Federal de Sergipe.</p>
        </fn>
      </fn-group>
    </back>
  </sub-article>
</article>
