cardiac – ABC CARDIOL

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Original Article

(-)-Carvone Modulates Intracellular Calcium Signaling with Antiarrhythmic Action in Rat Hearts

Gilmara Beatriz Andrade da Silva et al. Diego Santos Souza José Evaldo Rodrigues Menezes-Filho Júlio Alves da Silva-Neto … Jader dos Santos Cruz Danilo R. Roman-Campos Lucindo José Quintans-Júnior Carla Maria Lins de Vasconcelos

Abstract

Background:

(-)-Carvone is a monoterpene found in essential oils with antioxidant and anti-inflammatory activity.

Objective:

The aim of this paper was to analyze the antiarrhythmic property of (-)-carvone in the rat heart and its effects on the intracellular Ca²⁺ signaling.

Methods:

The effects of (-)-carvone were evaluated on the ventricular (0.5 mM) and atrial contractility (0.01 – 4 mM) and on electrocardiogram (0.5 mM). Fractional shortening, L-type calcium current (I_Ca,L) and Ca²⁺ signaling were measured in the isolated cardiomyocyte (0.5 mM). Antiarrhythmic effect was evaluated in arrhythmia model induced by calcium overload (0.5 mM) (n = 5). P < 0.05 was used as the significance level.

Results:

In the atrium, (-)-carvone evoked negative inotropism that was concentration-dependent (EC50 0.44 ± 0.11 mM) and decreased the positive inotropism evoked by CaCl₂ (0.1 to 8.0 mM) or BAY K8644 (5 to 500 nM), an agonist of L-type Ca²⁺ channel. In isolated heart, (-)-carvone (0.5 mM) promoted reduction of ventricular contractility (73%) and heart rate (46%), increased PRi (30.7%, time from the onset of the P wave until the R wave) and QTc (9.2%, a measure of the depolarization and repolarization of the ventricles) without changing the QRS complex duration. (-)-Carvone decreased the fractional shortening (61%), I_Ca,L (79%) and Ca²⁺ intracellular transient (38%). Furthermore, (-)-carvone showed antiarrhythmic action, verified by decrease of the arrhythmia score (85%) and occurrence of ventricular fibrillation.

Conclusion:

(-)-Carvone decreases Ca²⁺ entry through L-type Ca²⁺ channels, reducing the cardiac contractility and intracellular Ca²⁺, and, therefore, presenting promising antiarrhythmic activity in the rat hearts.

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Review Article

Screening, Diagnosis and Management of Atrial Fibrillation in Cancer Patients: Current Evidence and Future Perspectives

Pedro Gonçalves-Teixeira et al. Telma Costa Isabel Fragoso Diogo Ferreira … Mariana Brandão Adelino Leite-Moreira Francisco Sampaio José Ribeiro Ricardo Fontes-Carvalho

Abstract

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in the general population, carrying a high morbimortality burden, and this also holds true in cancer patients. The association between AF and cancer goes even further, with some studies suggesting that AF can be a marker of occult cancer. There is, however, a remarkable paucity of data concerning specific challenges of AF management in cancer patients. AF prompt recognition and management in this special population can lessen the arrhythmia-related morbidity and have an important prognostic benefit. This review will focus on current AF diagnosis and management challenges in cancer patients, with special emphasis on AF screening strategies and devices, and anticoagulation therapy with non-vitamin K antagonist oral anti-coagulants (NOACs) for thromboembolic prevention in these patients. Some insights concerning future perspectives for AF prevention, diagnosis, and treatment in this special population will also be addressed.

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Editorial

Current Atrial Fibrillation Ablation: An Alert for the Prevention and Treatment of Esophageal Lesions

Mauricio Scanavacca

Atrial fibrillation (AF) is recognized as the most frequent cardiac arrhythmia in clinical practice, and is responsible for the highest number of hospital admissions. In the general population, its prevalence is lower than 0.1% in individuals younger than 50 years, but increases exponentially with age, affecting about 8% of elderly individuals older than 80 years. Therefore, with the increase in the population’s life expectancy, a growing number of patients is or will be exposed to the risks of AF in the coming years.^,

The recent introduction of new anticoagulants has brought considerable advances in the prevention of cerebral embolism, the most severe complication of AF.^, However, the development of more effective antiarrhythmic drugs failed to show progress during this period. Therefore, a large number of patients still live with the limitations imposed by AF, including decreased quality of life due to symptoms such as palpitations, reduced functional capacity, or manifestations of cardiac insufficiency, in addition to the psychological problems proper of these conditions.^,

[…]

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Original Article

Evaluation of Electrocardiographic T-peak to T-end Interval in Subjects with Increased Epicardial Fat Tissue Thickness

Ozgur Kaplan et al. Ertugrul Kurtoglu Gokay Nar Erdogan Yasar … Gokhan Gozubuyuk Cem Dogan Ahmet Ugur Boz Sıho Hidayet Hasan Pekdemir

Abstract

Background:

The association between periatrial adiposity and atrial arrhythmias has been shown in previous studies. However, there are not enough available data on the association between epicardial fat tissue (EFT) thickness and parameters of ventricular repolarization. Thus, we aimed to evaluate the association of EFT thickness with indices of ventricular repolarization by using T-peak to T-end (Tp-e) interval and Tp-e/QT ratio.

Methods:

The present study included 50 patients whose EFT thickness ≥ 9 mm (group 1) and 40 control subjects with EFT thickness < 9 mm (group 2). Transthoracic echocardiographic examination was performed in all participants. QT parameters, Tp-e intervals and Tp-e/QT ratio were measured from the 12-lead electrocardiogram.

Results:

QTd (41.1 ± 2.5 vs 38.6 ± 3.2, p < 0.001) and corrected QTd (46.7 ± 4.7 vs 43.7 ± 4, p = 0.002) were significantly higher in group 1 when compared to group 2. The Tp-e interval (76.5 ± 6.3, 70.3 ± 6.8, p < 0.001), cTp-e interval (83.1 ± 4.3 vs. 76±4.9, p < 0.001), Tp-e/QT (0.20 ± 0.02 vs. 0.2 ± 0.02, p < 0.001) and Tp-e/QTc ratios (0.2 ± 0.01 vs. 0.18 ± 0.01, p < 0.001) were increased in group 1 in comparison to group 2. Significant positive correlations were found between EFT thickness and Tp-e interval (r = 0.548, p < 0.001), cTp-e interval (r = 0.259, p = 0.01), and Tp-e/QT (r = 0.662, p < 0.001) and Tp-e/QTc ratios (r = 0.560, p < 0.001).

Conclusion:

The present study shows that Tp-e and cTp-e interval, Tp-e/QT and Tp-e/QTc ratios were increased in subjects with increased EFT, which may suggest an increased risk of ventricular arrhythmia.

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Original Article

Does Ad Hoc Coronary Intervention Reduce Radiation Exposure? – Analysis of 568 Patients

Márcio A. M. Truffa et al. Gustavo M.P. Alves Fernando Bernardi Antonio Esteves Filho … Expedito Ribeiro Micheli Z. Galon André Spadaro Luiz J. Kajita Raul Arrieta Pedro A. Lemos

Background:

Advantages and disadvantages of ad hoc percutaneous coronary intervention have been described. However little is known about the radiation exposure of that procedure as compared with the staged intervention.

Objective:

To compare the radiation dose of the ad hoc percutaneous coronary intervention with that of the staged procedure

Methods:

The dose-area product and total Kerma were measured, and the doses of the diagnostic and therapeutic procedures were added. In addition, total fluoroscopic time and number of acquisitions were evaluated.

Results:

A total of 568 consecutive patients were treated with ad hoc percutaneous coronary intervention (n = 320) or staged percutaneous coronary intervention (n = 248). On admission, the ad hoc group had less hypertension (74.1% vs 81.9%; p = 0.035), dyslipidemia (57.8% vs. 67.7%; p = 0.02) and three-vessel disease (38.8% vs. 50.4%; p = 0.015). The ad hoc group was exposed to significantly lower radiation doses, even after baseline characteristic adjustment between both groups. The ad hoc group was exposed to a total dose-area product of 119.7 ± 70.7 Gycm2, while the staged group, to 139.2 ± 75.3 Gycm² (p < 0.001).

Conclusion:

Ad hoc percutaneous coronary intervention reduced radiation exposure as compared with diagnostic and therapeutic procedures performed at two separate times.

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Original Article

Clinical Differences between Subtypes of Atrial Fibrillation and Flutter: Cross-Sectional Registry of 407 Patients

Eduardo Dytz Almeida et al. Raphael Boesche Guimarães Laura Siga Stephan Alexandre Kreling Medeiros … Katia Foltz Roberto Tofani Santanna Leonardo Martins Pires Marcelo Lapa Kruse Gustavo Glotz de Lima Tiago Luiz Luz Leiria

Introduction:

Atrial fibrillation and atrial flutter account for one third of hospitalizations due to arrhythmias, determining great social and economic impacts. In Brazil, data on hospital care of these patients is scarce.

Objective:

To investigate the arrhythmia subtype of atrial fibrillation and flutter patients in the emergency setting and compare the clinical profile, thromboembolic risk and anticoagulants use.

Methods:

Cross-sectional retrospective study, with data collection from medical records of every patient treated for atrial fibrillation and flutter in the emergency department of Instituto de Cardiologia do Rio Grande do Sul during the first trimester of 2012.

Results:

We included 407 patients (356 had atrial fibrillation and 51 had flutter). Patients with paroxysmal atrial fibrillation were in average 5 years younger than those with persistent atrial fibrillation. Compared to paroxysmal atrial fibrillation patients, those with persistent atrial fibrillation and flutter had larger atrial diameter (48.6 ± 7.2 vs. 47.2 ± 6.2 vs. 42.3 ± 6.4; p < 0.01) and lower left ventricular ejection fraction (66.8 ± 11 vs. 53.9 ± 17 vs. 57.4 ± 16; p < 0.01). The prevalence of stroke and heart failure was higher in persistent atrial fibrillation and flutter patients. Those with paroxysmal atrial fibrillation and flutter had higher prevalence of CHADS2 score of zero when compared to those with persistent atrial fibrillation (27.8% vs. 18% vs. 4.9%; p < 0.01). The prevalence of anticoagulation in patients with CHA2DS2-Vasc ≤ 2 was 40%.

Conclusions:

The population in our registry was similar in its comorbidities and demographic profile to those of North American and European registries. Despite the high thromboembolic risk, the use of anticoagulants was low, revealing difficulties for incorporating guideline recommendations. Public health strategies should be adopted in order to improve these rates.

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Original Article

Electrophysiological Studies and Radiofrequency Ablations in Children and Adolescents with Arrhythmia

Mariana Fernandez Simão et al. Matheus Nardi Rios Tiago Luiz Luz Leiria Marcelo Lapa Kruse … Leonardo Martins Pires Roberto Tofani SantAnna Gustavo Glotz de Lima

Background:

Radiofrequency ablation is the standard non-pharmacological treatment for arrhythmias in pediatric patients. However, arrhythmias and their associated causes have particular features in this population.

Objective:

To analyze the epidemiological characteristics and findings of electrophysiological diagnostic studies and radiofrequency ablations in pediatric patients referred to the Electrophysiology Unit at Instituto de Cardiologia do Rio Grande do Sul, in order to characterize the particularities of this population.

Methods:

Cross-sectional study with 330 electrophysiological procedures performed in patients aged less than 20 years between June 1997 and August 2013.

Results:

In total, 330 procedures (9.6% of the overall procedures) were performed in patients aged less than 20 years (14.33 ± 3.25 years, age range 3 months to 19 years), 201 of which were males (60.9%). A total of 108 (32.7%) electrophysiological diagnostic studies were performed and of these, 48.1% showed abnormal findings. Overall, 219 radiofrequency ablations were performed (66.3%) with a success rate of 84.8%. The presence of an accessory pathway was the most prevalent finding, occurring in 158 cases (72.1%), followed by atrioventricular nodal reentrant tachycardia (16.8%), typical atrial flutter (3.1%) and extrasystoles originating from the right ventricular outflow tract (2.7%). Three patients developed complications during ablation (1.4%). Among congenital heart diseases, which occurred in 51 (15.4%) patients, atrial sept defect was the most frequent (27.4%), followed by ventricular sept defect (25.4%) and Ebstein’s anomaly (17.6%).

Conclusion:

Electrophysiological study and radiofrequency ablation are effective tools for diagnosis and treatment of arrhythmias in the pediatric population.

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Artigo Original

Relationship between Fibrosis and Ventricular Arrhythmias in Chagas Heart Disease Without Ventricular Dysfunction

Eduardo Marinho Tassi et al. Marcelo Abramoff Continentino Emília Matos do Nascimento Basílio de Bragança Pereira Roberto Coury Pedrosa

Background:

Patients with Chagas disease and segmental wall motion abnormality (SWMA) have worse prognosis independent of left ventricular ejection fraction (LVEF). Cardiac magnetic resonance (CMR) is currently the best method to detect SWMA and to assess fibrosis.

Objective:

To quantify fibrosis by using late gadolinium enhancement CMR in patients with Chagas disease and preserved or minimally impaired ventricular function (> 45%), and to detect patterns of dependence between fibrosis, SWMA and LVEF in the presence of ventricular arrhythmia.

Methods:

Electrocardiogram, treadmill exercise test, Holter and CMR were carried out in 61 patients, who were divided into three groups as follows: (1) normal electrocardiogram and CMR without SWMA; (2) abnormal electrocardiogram and CMR without SWMA; (3) CMR with SWMA independently of electrocardiogram.

Results:

The number of patients with ventricular arrhythmia in relation to the total of patients, the percentage of fibrosis, and the LVEF were, respectively: Group 1, 4/26, 0.74% and 74.34%; Group 2, 4/16, 3.96% and 68.5%; and Group 3, 11/19, 14.07% and 55.59%. Ventricular arrhythmia was found in 31.1% of the patients. Those with and without ventricular arrhythmia had mean LVEF of 59.87% and 70.18%, respectively, and fibrosis percentage of 11.03% and 3.01%, respectively. Of the variables SWMA, groups, age, LVEF and fibrosis, only the latter was significant for the presence of ventricular arrhythmia, with a cutoff point of 11.78% for fibrosis mass (p < 0.001).

Conclusion:

Even in patients with Chagas disease and preserved or minimally impaired ventricular function, electrical instability can be present. Regarding the presence of ventricular arrhythmia, fibrosis is the most important variable, its amount being proportional to the complexity of the groups.

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Artigo Original

Incidence of Ventricular Arrhythmias after Stem Cell Therapy in Patients with Chagas Cardiomyopathy

Adriana Sebba Barroso de Souza et al. Weimar Kunz Sebba Barroso Souza Sandra Araujo Costa Elis Marra de Moreira Freitas … Gustavo Carvalho Luís Antônio Batista Sá Salvador Rassi

Background:

Treatment with stem cells in several cardiomyopathies may be related to the increase in arrhythmias.

Objectives:

To determine whether intracoronary injection of stem cells in patients with Chagas cardiomyopathy is associated with increased incidence of ventricular arrhythmias, compared to the Control Group.

Methods:

A retrospective cohort study that evaluated the medical records of 60 patients who participated in a previous cross-sectional study. The following data were collected: age, gender, drugs used and Holter variables that demonstrated the presence of arrhythmias. Holter was performed in four stages: randomization, 2, 6 and 12 months segments. The Control Group received medical treatment and intracoronary injection of placebo and the Study Group had drug treatment and autologous stem cell implant.

Results:

There was no difference between Control Group and Study Group when analyzing the arrhythmia criteria. In the intra-group analysis, significant difference was found between the Holter tests of the Study Group for the variable total ventricular premature beats when compared with baseline, with p = 0.014 between Holter at randomization and Holter at 2 months, p = 0.004 between Holter at randomization and Holter at 6 months, and p = 0.014 between Holter at randomization and Holter at 12 months. The variable non-sustained ventricular tachycardia between Holter at randomization and Holter at 6 months showed p = 0.036.

Conclusion:

The intracoronary injection of stem cells did not increase the incidence of ventricular arrhythmias in patients with Chagas cardiomyopathy compared to the Control Group.

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Artigo Original

Ventricular repolarization in diabetic patients: characterization and clinical implications

David Clemente et al. Telmo Pereira Susana Ribeiro

BACKGROUND: Diabetes mellitus is a chronic and very common condition, and there has been lately a considerable increase in its prevalence and incidence. Diabetic patients have increased cardiovascular mortality, in which malignant ventricular arrhythmias seem to be implicated. OBJECTIVE: To study the effects of diabetes on ventricular repolarization parameters responsible for an increased susceptibility to malignant ventricular arrhythmias and/or sudden death. METHODS: We selected a group of 110 diabetic patients and a group of 110 controls with the same distribution of age, gender and race. We evaluated the following parameters of ventricular repolarization: QTmax, QTmean, QTmin, QTc max, QTc mean, QTc min, QT and QTc dispersions, Tpeak-Tend and jTpeak-jTend intervals (D II, V2 and V5), Tpeak-Tend and jTpeak-jTend dispersions. The electrocardiograms (ECG) were performed by the same operator and reviewed by the same observers. QT intervals were corrected according to Bazzet’s formula. RESULTS: We found significantly higher values of QTc max (p < 0.001), QTc mean (p < 0.001), QT dispersion (p < 0.001), QTc dispersion (p < 0.001), Tpeak-Tend dispersion ( p < 0.001), and jTpeak-jTend dispersion (p < 0.001) in diabetic patients than in controls. In diabetic patients, we observed prolonged values of QTc interval (5.5%), QT dispersion (0.9%), QTc dispersion (0%), Tpeak-Tend interval (7.3%), jTpeak-jTend interval (6.4%), Tpeak-Tend dispersion (16.4%), and jTpeak-jTend dispersion (12.7%). In the controls there were no prolonged values of any of the parameters. CONCLUSION: We concluded that diabetes causes prolongation and spatial dispersion of repolarization, and it may contribute to a greater ventricular electrical instability, whose expected clinical expression may be malignant ventricular arrhythmias.

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Artigo Original

Successful improvement of frequency and symptoms of premature complexes after oral magnesium administration

Cristina Nádja Muniz Lima De Falco et al. Cesar Grupi Eduardo Sosa Maurício Scanavacca … Denise Hachul Sissy Lara Luciana Sacilotto Cristiano F. Pisani José A. F. Ramires Francisco Darrieux

BACKGROUND: Premature ventricular and supraventricular complexes (PVC and PsVC) are frequent and often symptomatic. The magnesium (Mg) ion plays a role in the physiology of cell membranes and cardiac rhythm. OBJECTIVE: We evaluated whether the administration of Mg Pidolate (MgP) in patients with PVC and PsVC is superior to placebo (P) in improving symptoms and arrhythmia frequency. METHODS: Randomized double-blind study with 60 consecutive symptomatic patients with more than 240 PVC or PsVC on 24-hour Holter monitoring who were selected to receive placebo or MgP. To evaluate symptom improvement, a categorical and a specific questionnaire for symptoms related to PVC and PsVC was made. Improvement in premature complex density (PCD) per hour was considered significant if percentage reduction was >70% after treatment. The dose of MgP was 3.0 g/day for 30 days, equivalent to 260mg of Mg element. None of the patients had structural heart disease or renal failure. RESULTS: Of the 60 patients, 33 were female (55%). Ages ranged from 16 to 70 years old. In the MgP group, 76.6% of patients had a PCD reduction >70%, 10% of them >50% and only 13.4% <50%. In the P group, 40% showed slight improvement, <30%, in the premature complexes frequency (p < 0.001). Symptom improvement was achieved in 93.3% of patients in the MgP group, compared with only 16.7% in the P group (p < 0.001). CONCLUSION: Oral Mg supplementation decreases PCD, resulting in symptom improvement.

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Artigo Original

Morphology and contractility in cardiomyocytes of rats with low exercise performance

Judson Fonseca Quintão Júnior et al. Antônio José Natali Miguel Araújo Carneiro Júnior Cynthia Aparecida de Castro … Lucas Rios Drummond Victor Neiva Lavorato Leonardo Bonato Felix Jader dos Santos Cruz Thales Nicolau Prímola-Gomes

BACKGROUND: Aerobic capacity is essential to physical performance, and low aerobic capacity is related to the triggering of various cardiovascular diseases. OBJECTIVE: To compare the morphology and contractility of isolated rat cardiomyocytes with low performance and standard performance for exercise. METHODS: Wistar rats with 10 weeks of age underwent a protocol of treadmill running to fatigue, and were divided into two groups: Low Performance (LP) and Standard Performance (SP). Then, the animals were sacrificed, the heart was quickly removed and, by means of enzymatic dissociation, left ventricular cardiomyocytes were isolated. The cell and sarcomeres length and width of cardiomyocytes were measured using an edge detection system. The isolated cardiomyocytes were electrically stimulated at 1 and 3 Hz and cell contraction was measured by registering the change of their length. RESULTS: The cell length was shorter in the LP group (157.2 1.3µm; p < 0.05) compared to SP (161.4 1.3µm), and the same result was observed for the volume of cardiomyocytes (LP, 25.5 0.4. vs. SP, 26.8 ± 0.4 pL; p < 0.05). The time to peak contraction (LP, 116 1 vs. SP 111 2ms) and total relaxation (LP, 143 3 vs. SP 232 3ms) were higher in the LP group. CONCLUSION: We conclude that left ventricular myocytes of animals with low performance for exercise are smaller than animals with standard performance. In addition to that, they present losses in contractile capacity.

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Case Report

Echocardiographic features of non-compaction cardiomyopathy: missed and misdiagnosed disease

Francisco Martínez-Baca López et al. Rosa Marisol Alonso Bravo Domingo Arturo Rodríguez Huerta

Non-compaction cardiomyopathy is a rare disease, anatomically characterized by a prominent trabecular pattern and deep intertrabecular recesses. Its clinical manifestations include severe left ventricular dysfunction, arrhythmias, systemic embolism, and sudden death. In this report, two cases of patients of different ages with non-compaction cardiomyopathy are described: a male schoolboy whose pathology was associated with mitral stenosis and regurgitation and a 50-year-old female with history of high blood pressure and cardiac failure.

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Artigo Original

Morphometry of human myocardium in senile individuals

José Antonio Cardoso et al. Ana Elisa Toscano Tetsuo Tashiro Cláudio Antonio Ferraz de Carvalho Sílvia Regina Arruda de Moraes

OBJECTIVE: To carry out a quantitative assessment in human myocardium cells of senile individuals, in right, left and septal ventricular regions. METHODS: Five hearts from corpses of individuals without heart diseases, of both sexes, with age between 67 and 87 years old were used. The following parameters were assessed: myocyte unit cross section area (myoc. a o); myocyte unit perimeter length (myoc. l o); myocyte unit volume (myoc. v o); myocyte volumetric density (myoc. Vv); number of myocytes per volume unit (Nmm ^³myoc.). The t-test of Student was used in statistic analysis. RESULTS: The analysis of differences (p < 0.05) among right (RV), left (LV) and septal (S) ventricular regions of human heart showed that myoc. a o values were lower in RV (1.51 ± 0.10 µm²) and in S (1.55 ± 0.07 µm²) in relation to LV (1.84 ± 0.24 µm²). Values of myoc. l o were also shown lower in S (5.11 ± 0.46 µm) comparing to LV (6.2 ± 0.97 µm). Likewise, myoc. v o and myoc. Vv showed lower values in RV (88.75 ± 25.37 µm ³; 0.39 ± 0.03%) in relation to LV (122.41 ± 16.31 µm ³; 0.41 ± 0.01%). CONCLUSION: Results obtained show that there may be changes in dimensions of left ventricular wall myocyte cell during senescent stage. However, those differences are subtle and seem to mean the adjustment of tissue to functional changes that install along life.

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