Implantable cardioverter-defibrillators for treatment of sustained ventricular arrhythmias in patients with Chagas' heart disease: comparison with a control group treated with amiodarone alone

Abstract

Evidence is inconclusive concerning the benefit of implantable cardioverter-defibrillators (ICDs) for secondary prevention of mortality in patients with Chagas' heart disease (ChHD). The aim of this study was to compare the outcomes of ChHD patients with life-threatening ventricular arrhythmias (VAs), who were treated either with ICD implantation plus amiodarone or with amiodarone alone. The ICD group [76 patients; 48 men; age, 57 ± 11 years; left ventricular ejection fraction (LVEF), 39 ± 12%] and the historical control group treated with amiodarone alone (28 patients; 18 men; age, 54 ± 10 years; LVEF, 41 ± 10%) had comparable baseline characteristics, except for a higher use of beta-blockers in the ICD group (P < 0.0001). Amiodarone was also used in 90% of the ICD group. Therapy with ICD plus amiodarone resulted in a 72% reduced risk of all-cause mortality (P = 0.007) and a 95% reduced risk of sudden death (P = 0.006) compared with amiodarone-only therapy. The survival benefit of ICD was greatest in patients with LVEF < 40% (P = 0.01) and was not significant in those with LVEF ≥ 40% (P = 0.15). Appropriate ICD therapies occurred in 72% of patients and the rates of interventions were similar across patients with LVEF < 40% and ≥40%. Compared with amiodarone-only therapy, ICD implantation plus amiodarone reduced the risk of all-cause mortality and sudden death in ChHD patients with life-threatening VAs. Patients with LVEF < 40% derived significantly more survival benefit from ICD therapy. The majority of ICD-treated patients received appropriate therapies regardless of the LV systolic function.