Enhancing Cardiac Resynchronization Therapy for Patients with Atrial Fibrillation: The Role of AV Node Ablation.

Cardiac resynchronization therapy (CRT) has evolved as an effective therapy for patients with congestive heart failure (CHF) and ventricular dyssynchrony, currently defined as a wide QRS on the electrocardiogram. While multiple randomized controlled trials have confirmed the favorable effects of CRT on mortality and heart failure symptoms for patients in sinus rhythm, only recently observational studies have begun to suggest a similar benefit for patients with atrial fibrillation (AF) and dyssynchrony. Yet, implementing effective biventricular pacing in patients with AF can be problematic due to competing intrinsic AV conduction. For patients with depressed ejection fractions needing AV node (AVN) ablation to control fast ventricular rates, biventricular pacing has been shown to be superior to right ventricular pacing alone. When consistent pacing (over 90% of the time) cannot be achieved in AF patients due to a rapid ventricular response despite pharmacological therapy, AVN ablation should be considered. The additional benefit of performing AVN ablation to promote biventricular pacing in patients without rapid ventricular rates remains uncertain. A randomized controlled trial is needed to test the incremental benefit of AVN ablation to promote biventricular pacing in heart failure patients with AF and wide QRS.