Progression of heart failure in right univentricular pacing compared to biventricular pacing.

Background: Cardiac resynchronization therapy (CRT) improves hemodynamics and symptoms of heart failure by reducing ventricular dyssynchronity. Conversely, recent studies have demonstrated that right univentricular pacing in patients with an ejection fraction below 40% aggravates heart failure. In this retrospective study, we compared progression of disease in patients with mild to moderate heart failure that were treated with a right univentricular pacing device and patients with congestive heart failure that were treated with a biventricular system.