Effects of B-Blockers on outcome of patients with Chagas' cardiomyopathy with chronic heart failure

BackgroundA few studies have shown a beneficial effect of B-Blocker therapy on cardiac function and functional status in patients with chronic heart failure secondary to Chagas' cardiomyopathy.MethodsThe medical charts of patients routinely followed from January, 2000 to January, 2007 were reviewed to collect clinical, standard laboratory tests, 12-lead electrocardiogram, chest X-Ray, and Doppler echochardiogram variables. A Cox proportional hazards model was used to establish independent predictors of all-cause mortality for patients with Chagas' cardiomyopathy with chronic heart failure.ResultsA total of 231 consecutive patients were enrolled in the study. Median follow up was 19 (7, 46) months. Twenty (9%) patients underwent heart transplantation and 120 (52%) died during the investigation. Left ventricular systolic dimension (hazard ratio = 1.04; 95% confidence interval = 1.02 to 1.06; p < 0.005) and need of inotropic support (hazard ratio = 1.80; 95% confidence interval 1.2 to 2.60; p = 0,03), were positively associated, whereas B-Blocker therapy (HR = 0.34; 95% confidence interval 0.23 to 0.51; p < 0.0005) was negatively associated with mortality. Mortality was significantly lower in patients taking in comparison to those not taking B-Blockers. Patients taking a mean daily dose of carvedilol > or = to 9.375 mg had a marked decrease in mortality in comparison to those not on carvedilol therapy.ConclusionB-Blockers are effective, not detrimental, and may improve survival in Chagas' disease patients with chronic heart failure. A randomized trial is necessary to confirm these findings.