Evolução pós implante de cardiodesfibrilador implantavel em pacientes chagásicos e não-chagásicos: estudo comparativo

Abstract

Chagas disease is a major medical and social problems of Brazil. Sudden death is one of the clinical phenomena characteristic of Chagas disease since its initial descriptions. More than 50% of mortality in patients with Chagas' disease is attributable to sudden cardiac death. Implantable cardioverter-defibrillators (ICD) has become the maintherapeutic strategy for prevention of sudden death. However, the efficacy and safety of treating the patient with Chagas CDI was evaluated in a few observational studies. The aim of this study was to compare the outcome after ICD implantation in chagasic and non Chagasic. Design, population and methods: observational, longitudinal study. The population consisted of patients with and without Chagas indicating ICD for secondary prophylaxis; treated at a university hospital. The outcomes analyzed were appropriate therapy (appropriate shock therapy or pacing), inappropriate therapy, mortality, and inappropriate shock-free survival (appropriate therapy or death). Results: We evaluated 136 patients, 65 (54.6%) patients, with median follow-up of 266 (Q1= 72,25 and Q3 = 465.75) days. The median age was 60 (50-67) years and 96 patients (71%) were male. The two groups were similar regarding gender distribution, age, LVEF and follow up. There was appropriate therapy triggered by the ICD in 32 (62.7%) patients with and 19 (37.3%) non Chagasic patients (p = 0.005). Chagas' heart disease increased by 2.7 times (95% CI 1.3 - 5.6), the risk of patients receiving appropriate therapy. Chagas disease patients withand without ventricular dysfunction showed the same rate of appropriate therapy (p = 0.65). Inappropriate therapy occurred in only five (3.7%) cases and no difference between groups (p = 0.23). There were 16 deaths (11.8%) and no difference between groups (p = 0.82). Chagas disease patients had significantly lower event-free survival when compared to non-Chagasic patients (p = 0.004). The only independent variable predictive of events was to be patient with congenital heart disease (p = 0.01, HR = 2.24, CI 95% = 1,2-4,2). Conclusions: The increased frequency of chronic Chagas record appropriate therapy andthe difference in event-free survival between the groups, are consistent with the presence of an arrhythmogenic substrate worse in Chagas heart disease. The CDI appears to provide effective protection to patients with Chagas disease, providing safe procedure with low frequency of inappropriate therapy and complications. The lack of difference in the rate of appropriate therapy, among Chagasic patients with and without ventricular dysfunction suggests that LVEF should not be used as a criterion leading and decisive indication of the defibrillator in these patients. Considering that Chagas disease was the only independentpredictor of appropriate therapy and death, questions the ethics of undergoing chagasic patients with indication for secondary prevention of sudden death in randomized trials in which one group will not receive this treatment .