Outcome of right ventricular bifocal pacing in patients with permanent atrial fibrillation and severe dilated cardiomiopathy due to Chagas disease: three years of follow-up.

Objectives Of Study: Several studies have shown that heart failure may benefit from cardiac resynchronization therapy (CRT). Studies have demonstrated a beneficial effect of right ventricular (RV) bifocal pacing, using two leads at different positions, in similar patient populations. The aim was to evaluate this approach in Chagas disease patients who developed both severe dilated cardiomiopathy and chronic atrial fibrillation.

Methods: The study included 30 patients with a mean age of 52 +/- 6 years (16 male), who had atrioventricular block at functional class II or IV (NYHA). Patients underwent endocardial dual-chamber pacemaker implantation with two RV leads-one placed near the RV outflow tract and the other in the apex. Patients were examined by echocardiography, 24-hour Holter, and New York Heart Association (NYHA) class determination before and 3, 6, 12, 18, 24, and 36 months after CRT.

Results: Compared to the baseline, the left ventricular ejection fraction increased in the first month of CRT, the left ventricular end diastolic diameter decreased, all patients were downgraded to NYHA class I or II, and the incidence of ventricular arrhythmias decreased. However, these could not be maintained and worsened after 6 months CRT. There was a mortality rate of 43.3% during the first year, and only 23.3% of patients remained alive after 3 years. They underwent an electrophysiological study, which revealed complex arrhythmias justifying implantable cardioverter defibrillator (ICD) in six out of seven patients.

Conclusion: The favorable effects of RV bifocal pacing could not be maintained beyond the first 6 months, likely due to the ventricular arrhythmias. Therefore, CRT combined with ICD from the outset may be recommended for this patient group.