Exercise stress test prognostic factors in Chagas cardiomyopathy with left ventricular dysfunction

Background: Chagas disease has multiple presentations, and only 10% progress to left ventricular (LV) dysfunction. The exercise stress test (EST) has been underutilized as a prognostic tool for this disease. Objective: To study the main prognostic variables of EST in Chagas cardiomyopathy with LV dysfunction using all-cause death as the endpoint. Methods: This was a prospective cohort study. The EST was performed with the modified Bruce protocol and passive recovery after exertion. The variables analyzed in the EST were stress time, chronotropic index, heart rate recovery (HRR), systolic blood pressure (SBP) recovery, SBP curve on stress, and electrocardiographic changes. We used Cox regression analysis to determine the risk of death after adjusting for demographic variables, cardiovascular risk factors, medications, and LV ejection fraction. Results: A total of 46 patients were eligible. The mean age was 57.70 (SD 9.22) years; 25 (54.3%) were women, and 42 (91.3%) were using beta-blockers. Fourteen (30.4%) deaths were recorded during the total follow-up period of 68 months. The variables found to be independently associated with lower risk of death were exercise time > 6.5 minutes (HR = 0.286; 95% CI 0.086-0.952; p = 0.041) and HRR & GE; 8 bpm (HR = 0.146; 95% CI 0.036-0.585; p = 0.007). Conclusion: EST can be a useful prognostic tool in Chagas cardiomyopathy with LV dysfunction in terms of stress time and HRR.