Heart Rate – ABC CARDIOL

IJCS

Original Article

Heart Rate Reactivity to Acute Mental Stress is Associated With Parasympathetic Withdrawal and Adiposity in Firefighters

Haissa A. Mendes et al. Natália E. Canto Luiz Rodrigo A. Lima Guilherme F. Speretta

Abstract

Background

Firefighters are regularly exposed to stress and have a high incidence of cardiovascular events. Investigating cardiovascular and autonomic reactivity to acute mental stress (AMS) and its association with adiposity may contribute to explaining the increased cardiovascular risk in these professionals.

Objectives

To evaluate cardiovascular and autonomic reactivity to AMS in firefighters while considering adiposity parameters.

Methods

This study recorded the blood pressure and heart rate (HR) of twenty-five firefighters (38±8 years) at rest, while performing the Stroop color-word test to induce AMS, and recovery. Cardiac autonomic modulation (HR variability), baroreflex sensitivity (BRS — sequential method), and adiposity (electrical bioimpedance) were assessed. One-way or two-way analysis of variance followed by Tukey’s post hoc test and multiple linear regression were performed. The significance level was P<0.05.

Results

The AMS increased mean arterial pressure (MAP — Δ16±13 mmHg) and HR (Δ14±7 bpm) ( P <0.05). These responses were associated with parasympathetic modulation withdrawal (RMSSD: baseline: 29.8±18 vs. AMS: 21.5±14 ms; High-frequency: baseline: 5.2±1.4 vs. AMS: 4.5±1.3 Ln ms ² ; P <0.05) and decreased in the Up gain of the baroreflex (baseline: 8.9±5.1 vs. AMS: 6.3±3.0 mmHg/ms; P <0.05). Groups divided by HR reactivity peak showed parasympathetic modulation withdrawal only in firefighters with lower adiposity (RMSSD: baseline: 27.8±17.6 vs. AMS: 14.4±9.2 ms; High-Frequency: baseline: 5.3±1.2 vs. AMS: 3.8±1.4 Ln ms ² ; P <0.05). Fat percentage (β = -0.499), BRS (β = 0.486), and sympathetic/parasympathetic balance (β = -0.351) were predictors of HR reactivity ( P <0.05).

Conclusion

Our results demonstrated that HR reactivity to AMS modulated by cardiac vagal withdrawal seems to be influenced by body composition in this group of firefighters.

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IJCS

Editorial

Safety of Dental Anesthesia in ICD Recipients

Ricardo Alkmim Teixeira

Some anesthetic agents administered during general anesthesia can cause heart rhythm disorders, mainly associated with autonomic imbalance. Off-target cardiac sodium channel blockade is considered the canonical mechanism behind cardiotoxicity.

Lidocaine, the most common local anesthetic, produces a transient loss of sensory, motor, and autonomic function when the drug is injected or applied close to neural tissues; furthermore, it has a good safety margin before reaching toxic blood levels. However, care must be taken to keep track of the total dose given to minimize its systemic toxicity. In addition to direct nerve toxicity, systemic toxicity affecting the brain and/or cardiac muscle can also occur. Cardiovascular toxicity usually appears as tachycardia and hypertension; however, with increasing toxicity, bradycardia and hypotension can occur. Ventricular arrhythmias and cardiac arrest also have been described. Because of its potential effects upon the heart, it is also commonly used as an antiarrhythmic agent to depress ventricular arrhythmias in controlled doses.

[…]

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IJCS

Original Article

Dysautonomia Evaluation by Holter in Chagas Heart Disease

Michele Alves Rocha de Oliveira et al. Thais Aguiar Nascimento Gilson Soares Feitosa-Filho Luiz Eduardo Fonteles Ritt … Constança Margarida Sampaio Cruz Mário de Seixas Rocha

Abstract

Background

Sudden cardiac death is the main lethal mechanism associated with Chagas cardiomyopathy. Studies suggest that dysautonomia may represent a relevant, intense, independent, and early phenomenon in the natural history of the disease, even when ventricular systolic function is preserved, and may also be the mechanism that triggers malignant ventricular arrhythmias.

Objective

To evaluate the degree of dysautonomia and its possible association with ventricular arrhythmias in patients with Chagas cardiomyopathy, according to different categories of mortality risk, as defined by the score proposed by Rassi, used as a surrogate outcome for death.

Methods

A cross-sectional study involving 43 patients with Chagas cardiomyopathy stratified into risk categories based on the Rassi score, with 23 being classified as low risk and 20 as intermediate-to-high risk. Heart rate variability (HRV) was assessed using Holter monitoring for long-term recordings of 24 hours (time domain) and for short-term recordings of 5 minutes (frequency domain) at rest and after autonomic tests: deep breathing and Valsalva maneuver. The HRV variables were compared between the groups using the Student’s t-test and α=0.05.

Results

Comparison of the results between the risk stratification groups showed no differences in HRV indexes, either in the time or frequency domain. However, results showed a significant increase in the number of arrhythmias as a function of increased risk (p=0.02).

Conclusion

There was no association between the degree of dysautonomia, evaluated by Holter monitoring, and the categories of mortality risk, despite a direct association between the rate of arrhythmias and the higher risk group.

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IJCS

Original Article

Impact of Air Pollutant on Heart Rate Variability in Healthy Young Adults

Anita de Cássia Melinski et al. Aparecida Maria Catai Sílvia Cristina Garcia de Moura Juliana Cristina Milan-Mattos Monica Yuri Takito

Abstract

Background:

Air pollution and sex independently affect cardiac autonomic control, which can be assessed by heart rate variability (HRV). The research hypothesis is that individuals exposed to low concentrations of pollution have higher cardiac autonomic modulation compared to those exposed to high concentrations and that women have better cardiac autonomic control than men.

Objective:

To analyze the impact of exposure to air pollutants, specifically smoke, and sex on HRV in healthy young people exposed to different concentrations of pollution over an average period of 22 years.

Methods:

From April to September 2011, 36 participants of both sexes (20-30 years old) were selected, grouped by levels of air pollution exposure according to indices provided by the Environmental Company of São Paulo State. The R-R intervals (R-Ri) of the electrocardiogram were captured using a heart rate monitor during supine rest. HRV was analyzed by spectral analysis and conditional entropy. The Queen’s College step test was used to characterize functional capacity. A between-group comparison was performed using the two-way ANOVA statistical test (post hoc Tukey) and p<0.05.

Results:

Significant differences were found in mean R-Ri (p<0.01) and cardiac parasympathetic modulation between sexes in the same city (p=0.02) and between groups exposed to different air pollution concentrations (p<0.01).

Conclusion:

Our results suggest that long-term exposure to air pollutants, specifically smoke, has an unfavorable impact on HRV, with reduced cardiac vagal autonomic modulation in healthy young adults, especially females.

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IJCS

Brief Communication

Increased Maximal Expiratory Pressure, Abdominal and Thoracic Respiratory Expansibility in Healthy Yoga Practitioners Compared to Healthy Sedentary Individuals

Cláudia Fetter et al. Liliane Appratto de Souza Daniela Ravizzoni Dartora Andressa Schein … Bruna Eibel Karina Casali Maria Cláudia Irigoyen

Abstract

Background

Increasing thoracic expansion is effective at reducing blood pressure in hypertensive subjects. Yoga prescribes many respiratory techniques with a growing number of practitioners. However, very little is known whether sedentary or yoga practitioners show measurable differences in their respiratory patterns.

Objective

This study aims to demonstrate differences between healthy sedentary individuals and healthy yoga practitioners regarding maximal respiratory pressures and thoracic and abdominal respiratory expansibility.

Methods

Maximal inspiratory and expiratory pressures (MIP and MEP, respectively) were evaluated by manovacuometry, while respiratory expansion was assessed by the cirtometry of abdominal (CA), thoracic xiphoidal (CTX), and thoracic axillary (CTA) circumferences at rest (end expiratory moment) and at full inspiration in healthy sedentary individuals (SED) and yoga practitioners (YOGA). A delta derived from rest and full inspiration measures (ΔCA, ΔCTX, and ΔCTA, respectively), followed by a percentage of each item (ΔCA/CA, ΔCTX/CTX, and ΔCTA/CTA) was then calculated. Groups were compared by means of an unpaired Student’s t-test, with a significance level p < 0.05.

Results

All respiratory expansion measures were significantly higher in in the YOGA group. A significantly higher MEP (cmH₂O) was also detected in yoga practitioners: SED 89.3 ± 19.3 and YOGA 114.7 ± 24.8 ( p = 0.007), along with decreased heart rate at rest (bpm): SED 84±6 and YOGA 74±15 ( p = 0.001).

Conclusions

Yoga practitioners have shown greater thoracic and abdominal expansion and increased MEP, when compared to healthy sedentary individuals, as well as significantly lower heart rates at rest and body mass index (BMI). However, whether or not these findings are related to respiratory patterns is uncertain.

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IJCS

Case Report

Linear and Nonlinear Heart Rate Variability Analysis in Gonadal Dysgenesis (Swyer Syndrome): A Case Report

Valdelias Xavier Pereira et al. Tatiana Dias de Carvalho Marcos Antonio Marinovic Junior Alex Rey Norberto … José Maria Soares Júnior Vitor Engrácia Valenti Isabel Cristina Esposito Sorpreso

Abstract

Swyer syndrome is one of the disorders of sexual differentiation. Previous studies have demonstrated increased sympathetic activity with heart rate variability (HRV) analysis with decreasing estradiol levels. One patient presented a pure 46, XY gonadal dysgenesis with female phenotype. Cardiac autonomic modulation was assessed through HRV analysis while at rest. This research analyzed linear and nonlinear indexes. HRV analysis showed reduced parasympathetic and global modulation with an apparent increase in sympathetic tone and a loss of HR fractal dynamics toward correlated behavior, characterized by low entropy and high determinism of time series.

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IJCS

Original Article

Cardiac Autonomic Modulation of Healthy Individuals and Patients with Chronic Obstructive Pulmonary Disease During Spontaneous and Controlled Breathing

Mario Augusto Paschoal et al. Livea Gianfrancesco Luisa Torres Camargo Náira Bueno Seixas Ana Beatriz Paschoal

Abstract

Background:

Lung diseases and different forms of breathing may interfere with cardiac autonomic modulation (CAM).

Objective:

To compare CAM in individuals with chronic obstructive pulmonary disease (COPD) with healthy individuals during spontaneous breathing (SB) and controlled breathing (CB).

Methods:

Cross-sectional study involving 30 individuals selected by convenience, divided into COPD group (n = 19) and control group (CG; n = 12). All participants were submitted to heart beat recordings during five minutes at rest (SB) and another five minutes during CB performed at six cycles/min. CAM was made by assessment of the heart rate variability (HRV) through time domain (TD) and frequency domain (FD). Comparisons between groups were performed by Mann Whitney test, and significance level was set at p < 0.05.

Results:

During SB, HRV TD and FD indices were higher in the controls than in the COPD group, respectively – RR intervals (53.2 ms versus 36.6 ms), RMSSD (42.1 ms versus 26.6 ms) (p < 0.05), total power (28322.8 ms²/Hz versus 2011.6 ms²/Hz), and high-frequency band (800.5 ms⁽²⁾ versus 330.7 ms²). During CB, the CG also showed higher values for the TD parameters pNN50 (11.7% versus 5.1%), RMSSD (48.3 ms versus 26.7 ms), and SD of RRi (64.9 ms versus 44.7 ms), as well as for the low-frequency component of FD analysis (2848.6 ms² versus 1197.9 ms²).

Conclusion:

COPD patients have different CAM when compared with healthy individuals during spontaneous (SB) and controlled breathing (CB).

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IJCS

Original Article

Neuromuscular Electrical Stimulation on Hemodynamic and Respiratory Response in Patients Submitted to Cardiac Surgery: Pilot Randomized Clinical Trial

Telma Cristina Fontes Cerqueira et al. Manoel Luiz de Cerqueira Neto Auristela Julia Guilhermino Carvalho Géssica Uruga Oliveira … Amaro Afrânio de Araújo Filho Vitor Oliveira Carvalho Lucas de Assis Pereira Cacau Walderi Monteiro da Silva Júnior José Teles de Mendonça Valter Joviniano de Santana Filho

Abstract

Background:

Neuromuscular electrical stimulation seems to be a promising option to intensify the rehabilitation and improve the exercise capacity of patients in the immediate postoperative period of cardiac surgery.

Objective:

This study aimed to evaluate the hemodynamic (heart rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure) and respiratory (respiratory rate and oxygen saturation) responses to neuromuscular electrical stimulation in the immediate postoperative period in patients submitted to cardiac surgery and to verify its feasibility and safety.

Methods:

This is a pilot randomized controlled trial, wherein critical patients in the immediate postoperative period of cardiac surgery were randomly assigned to a control group, using sham neuromuscular electrical stimulation, or an experimental group, submitted to neuromuscular electrical stimulation sessions (FES), for 60 min, with a 50-Hz frequency, 200-µs pulse duration, time on: 3 s, and time off: 9 s. Data distribution was evaluated by the Shapiro-Wilk test. The analysis of variance was used and a p-value < 0.05 was considered significant.

Results:

Thirty patients were included in the study. The neuromuscular electrical stimulation was applied within the first 23.13 ± 5.24 h after cardiac surgery, and no changes were found regarding the hemodynamic and respiratory variables between the patients who underwent neuromuscular electrical stimulation, and those in the control group.

Conclusions:

In the present study, neuromuscular electrical stimulation did not promote changes in hemodynamic and respiratory responses of patients in the immediate postoperative period of cardiac surgery.

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ABC

Original Article

Electrocardiographic and Blood Pressure Alterations During Electroconvulsive Therapy in Young Adults

Demetrio Ortega Rumi et al. Maria Cecília Solimene Júlio Yoshio Takada César José Grupi … Dante Marcelo Giorgi Sérgio Paulo Rigonatti Protásio Lemos da Luz José Antonio Franchini Ramires

OBJECTIVE – To study cardiovascular alterations in young patients with no apparent organic disease who underwent electroconvulsive therapy. METHODS – The study comprised 47 healthy patients (22 males and 25 females) with a mean age of 30.3 years, who underwent electroconvulsive therapy. Ambulatory blood pressure monitoring and continuous electrocardiographic monitoring (Holter monitor) were performed during 24 hours. Blood pressure and heart rate were assessed 4 hours prior to electric shock administration, during electric shock administration, and 3 hours after electric shock administration. Arrhythmias and alterations in the ST segment in 24 hours were recorded. RESULTS – On electroconvulsive therapy, a significant increase in blood pressure and heart rate was observed and the measurements returned to basal values after 25 minutes. Three females had tracings with depression of the ST segment suggesting myocardial ischemia prior to and after electroconvulsive therapy. Coronary angiography was normal. No severe cardiac arrhythmias were diagnosed. CONCLUSION – 1) Electroconvulsive therapy is a safe therapeutic modality in psychiatry; 2) it causes a significant increase in blood pressure and heart rate; 3) it may be associated with myocardial ischemia in the absence of coronary obstructive disease; 4) electroconvulsive therapy was not associated with the occurrence of severe cardiac arrhythmias.

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