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

BACKGROUND: A 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.
METHODS: The 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.
RESULTS: A 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 9.375mg had a marked decrease in mortality in comparison to those not on carvedilol therapy.
CONCLUSION: B-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.