Márcia Maria Oliveira Lima

A randomized trial of the effects of exercise training in Chagas cardiomyopathy

The effects of exercise training in chronic heart failure are well established, however, they have not been evaluated in Chagas cardiomyopathy (ChC). We sought to determine the effects of exercise training on functional capacity, health‐related quality of life (HQoL), and brain natriuretic peptide (BNP) levels in patients with ChC.

Left Ventricular Diastolic Function and Exercise Capacity in Patients with Chagas Cardiomyopathy

Parameters of diastolic function have been shown to correlate with exercise capacity (EC) in individuals with impaired left ventricular (LV) systolic function. However, the role of LV diastolic function in predicting EC in Chagas cardiomyopathy has not been reported. Objectives: This study aimed to determine the relationship between LV diastolic parameters assessed by echocardiography and EC in patients with Chagas cardiomyopathy. Methods: We studied 40 patients (23 men; 49 ± 8 years), with diagnosis of Chagas disease and dilated cardiomyopathy. Medical therapy was individually adjusted according to standardized guidelines. Methods of acquiring two‐dimensional Doppler, tissue Doppler imaging (TDI), and their measurements were described. Exercise testing was performed by a Bruce protocol. Brain natriuretic peptide (BNP) levels were also determined. Results: Most patients (63%) were in NYHA functional class I. Mean peak oxygen consumption estimated (peakVO2) was 31.7 ± 10.2 mL/kg per minute, and mean left ventricular ejection fraction (LVEF) was 36.3 ± 7.8%. Univariate analysis showed that various echocardiographic parameters of diastolic function were correlated with peakVO2. There was no correlation between BNP levels or LVEF and EC. Multivariate analysis, after adjustment for age and gender, revealed that E/E′ ratio and left atrial volume (LAV), emerged as independent predictors of EC, as demonstrated in the model: peakVO2= 60.825 + (0.439 × LAV) − (1.620 × E/E′ ratio) − (0.483 × age) − (4.821 × female gender). The R2 of this model was 0.52. Conclusions: Functional capacity assessed by peakVO2 was related to increase LV filling pressures, independently on systolic function in patients with Chagas cardiomyopathy. (Echocardiography 2010;27:519‐524)

Functional capacity and right ventricular function in patients with Chagas heart disease

AIMS Right ventricular (RV) dysfunction is an important factor on effort tolerance in cardiopulmonary diseases. Nevertheless, the role of RV function in predicting exercise capacity in patients with Chagas disease has not been reported. This study aims to evaluate whether RV function assessed by tissue Doppler can predict functional capacity in patients with Chagas heart disease. METHODS AND RESULTS We evaluated 65 patients (48.6 +/- 9.1 years, 60% men) with Chagas heart disease. Standard and tissue Doppler echocardiography were performed before maximal exercise testing. Tissue Doppler imaging (TDI) was used to measure RV peak annular systolic and diastolic velocities. Exercise testing was performed using a standard Bruce protocol. Linear regression analysis was used to determine multivariate peak oxygen consumption (VO(2)) predictors. All patients were in NYHA functional class I or II. Mean peak VO(2) was 32.4 +/- 10.2 mL/kg/min and mean LV ejection fraction was 43 +/- 11%. There was correlation between TDI RV peak systolic velocity and LV ejection fraction (r = 0.5; P < 0.001). In a multivariate analysis, after adjustment for age and gender, RV function emerged as an independent predictor of functional capacity, as demonstrated in the model: peak VO(2) (r = 0.71) was: 42.22-(9.77 x female gender)-(0.29 x age) + (1.54 x RV systolic velocity). CONCLUSION In this cross-sectional study, RV function was an important, independent determinant of exercise capacity in patients with Chagas heart disease. TDI RV systolic annular velocity was most closely associated with peak VO(2), regardless of the influence of age, gender, and other echocardiographic parameters.

Improvement of the functional capacity is associated with BDNF and autonomic modulation in Chagas disease

35%) [2] must be considered. The power of these findings are limited by thesmall numberof patientswithmoderate airways reversibility (n=4). However,we take some reassurance from the goodproportionof patients diagnosed with asthma recruited to the study. Despite the limitation, we believe our study provides important hypothesis-generating data that contributes to a paucity of relevant literature in this area. A larger long-term study is required to provide definitive data regarding the effect of nebivolol on CHF patients withmoderate reversibility airways disease.

Exercício aeróbico no controle da hipertensão arterial na pós-menopausa

OBJECTIVE: To evaluate the effect of the aerobic exercise training on functional capacity (FC) and blood pressure (BP) control in hypertensive stage I or controlled hypertension postmenopausal women in a primary care unit (PCU). METHODS: Before and after 12 weeks of aerobic exercise training in a PCU, 10 hypertensive postmenopausal women age 56.9 ± 5.98, sedentary, non-users of hormone replacement therapy were submitted to: the evaluation of the body mass index (BMI); the waist circumference (WC); the FC by ergometric test (oxygen uptake/VO2, duration of the test) and six minute walk test (walked distance); and repeated casual measures of BP. Revaluations were made for each 30 days. Data were presented in mean and standard deviation and analyzed by Kolmogorov-Smirnov test, paired Students t-test, Wilcoxon and a repeated-measures ANOVA considering p < 0.05. RESULTS: No significant difference was found in BMI (p = 0.40) and WC (p = 0.74) after training. However, after 30 days, a reduction had already been observed in systolic BP (from 142.70 ± 6.25 to 130.76 ± 5.80 mmHg, p < .001) and diastolic (from 87.03 ± 4.48 to 81.90 ± 4.30 mmHg, p = .002) and also a significant improvement of functional capacity by VO2 (from 24.90 ± 6.38 to 27.82 ± 6.14 mL/kg/min, p = .028), duration of the test (from 6.89 ± 1.78 to 7.70 ± 1.80 min, p = .022) and distance walked (from 511.07 ± 41.99 to 556.1 ± 43.19 m, p = .009). CONCLUSION: The aerobic exercise training program in a primary care unit was effective and viable as a strategy to reduce the BP and to improve the functional capacity in hypertensive postmenopausal women.

Effects of Exercise Training on Heart Rate Variability in Chagas Heart Disease

Background: Heart rate variability (HRV) is a marker of autonomic dysfunction severity. The effects of physical training on HRV indexes in Chagas heart disease (CHD) are not well established. Objective: To evaluate the changes in HRV indexes in response to physical training in CHD. Methods: Patients with CHD and left ventricular (LV) dysfunction, physically inactive, were randomized either to the intervention (IG, N = 18) or control group (CG, N = 19). The IG participated in a 12-week exercise program consisting of 3 sessions/week. Results: Mean age was 49.5 ± 8 years, 59% males, mean LVEF was 36.3 ± 7.8%. Baseline HRV indexes were similar between groups. From baseline to follow-up, total power (TP): 1653 (IQ 625 - 3418) to 2794 (1617 - 4452) ms, p = 0.02) and very low frequency power: 586 (290 - 1565) to 815 (610 - 1425) ms, p = 0.047) increased in the IG, but not in the CG. The delta (post - pre) HRV indexes were similar: SDNN 11.5 ± 30.0 vs. 3.7 ± 25.1 ms. p = 0.10; rMSSD 2 (6 - 17) vs. 1 (21 - 9) ms. p = 0.43; TP 943 (731 - 3130) vs. 1780 (921 - 2743) Hz. p = 0.46; low frequency power (LFP) 1.0 (150 - 197) vs. 60 (111 - 146) Hz. p = 0.85; except for high frequency power, which tended to increase in the IG: 42 (133 - 92) vs. 79 (61 - 328) Hz. p = 0.08). Conclusion: In the studied population, the variation of HRV indexes was similar between the active and inactive groups. Clinical improvement with physical activity seems to be independent from autonomic dysfunction markers in CHD.

Respiratory function and functional capacity in Chagas cardiomyopathy.

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Exercise-induced ventricular arrhythmias and vagal dysfunction in Chagas disease patients with no apparent cardiac involvement

INTRODUCTION Exercise-induced ventricular arrhythmia (EIVA) and autonomic imbalance are considered as early markers of heart disease in Chagas disease (ChD) patients. The objective of the present study was to verify the differences in the occurrence of EIVA and autonomic maneuver indexes between healthy individuals and ChD patients with no apparent cardiac involvement. METHODS A total of 75 ChD patients with no apparent cardiac involvement, aged 44.7 (8.5) years, and 38 healthy individuals, aged 44.0 (9.2) years, were evaluated using echocardiography, symptom-limited treadmill exercise testing and autonomic function tests. RESULTS The occurrence of EIVA was higher in the chagasic group (48%) than in the control group (23.7%) during both the effort and the recovery phases. Frequent ventricular contractions occurred only in the patient group. Additionally, the respiratory sinus arrhythmia index was significantly lower in the chagasic individuals compared with the control group. CONCLUSIONS ChD patients with no apparent cardiac involvement had a higher frequency of EIVA as well as more vagal dysfunction by respiratory sinus arrhythmia. These results suggest that even when asymptomatic, ChD patients possess important arrhythmogenic substrates and subclinical disease.

Heart rate recovery in asymptomatic patients with Chagas disease.

Background Chagas disease patients with right bundle-branch block (RBBB) have diverse clinical presentation and prognosis, depending on left ventricular (LV) function. Autonomic disorder can be an early marker of heart involvement. The heart rate recovery (HRR) after exercise may identify autonomic dysfunction, with impact on therapeutic strategies. This study was designed to assess the HRR after symptom-limited exercise testing in asymptomatic Chagas disease patients with RBBB without ventricular dysfunction compared to patients with indeterminate form of Chagas disease and healthy controls. Methods One hundred and forty-nine subjects divided into 3 groups were included. A control group was comprised of healthy individuals; group 1 included patients in the indeterminate form of Chagas disease; and group 2 included patients with complete RBBB with or without left anterior hemiblock, and normal ventricular systolic function. A symptom-limited exercise test was performed and heart rate (HR) response to exercise was assessed. HRR was defined as the difference between HR at peak exercise and 1 min following test termination. Results There were no differences in heart-rate profile during exercise between healthy individuals and patients in indeterminate form, whereas patients with RBBB had more prevalence of chronotropic incompetence, lower exercise capacity and lower HRR compared with patients in indeterminate form and controls. A delayed decrease in the HR after exercise was found in 17 patients (15%), 9% in indeterminate form and 24% with RBBB, associated with older age, worse functional capacity, impaired chronotropic response, and ventricular arrhythmias during both exercise and recovery. By multivariable analysis, the independent predictors of a delayed decrease in the HRR were age (odds ratio [OR] 1.11; 95% confidence interval [CI] 1.03 to 1.21; p = 0.010) and presence of RBBB (OR 3.97; 95% CI 1.05 to 15.01; p = 0.042). Conclusions A small proportion (15%) of asymptomatic Chagas patients had attenuated HRR after exercise, being more prevalent in patients with RBBB compared with patients in indeterminate form and controls.

Reduced functional capacity in patients with Chagas disease: a systematic review with meta-analysis

Reduced peak oxygen uptake (VO2peak) is a common clinical finding in progressive Chagas disease. However, the disease stage in which functional impairment is detectable remains uncertain. The present study compared functional capacity between healthy controls and patients with different clinical forms of Chagas disease. A systematic review and meta-analysis (PROSPERO database CRD42017058353) was conducted following a search of the MEDLINE, Web of Science, CINAHL, and LILACS databases from September to December 2017 for articles published in English, Spanish, or Portuguese, with no date restrictions. We included studies that compared the VO2peak between healthy and Chagas disease patients, stratified according to 3 clinical forms [no apparent cardiac disease, non-dilated Chagas heart disease (CHD), and dilated CHD]. Seven cross-sectional studies were included. Chagas disease patients without apparent cardiac disease (n=208) had VO2peak values [mean difference, -1.55ml/kg/min; 95% confidence interval (CI), -4.98ml/kg/min to 1.88ml/kg/min] similar to those of healthy controls (n=105; p=0.38, I2=52%). In non-dilated CHD (n=159), VO2peak was 8.71ml/kg/min lower (95% CI, -13.99 to -3.42ml/kg/min) than in healthy controls (n=59; p=0.001, I2=75%). VO2peak was also significantly lower (mean difference, -9.30ml/kg/min; 95% CI, -11.34 to -7.25ml/kg/min) in dilated CHD patients (n=131) than in healthy controls (n=53; p<0.001, I2=0%). Exercise capacity in Chagas disease patients without apparent cardiac disease is similar to that in healthy controls. Functional impairment in Chagas disease is detectable in the early stages of cardiac involvement, even in the absence of systolic dysfunction and signs of heart failure.