Atrial Fibrillation During Cardiac Resynchronization Therapy

The landmark trials on cardiac resynchronization therapy (CRT) have focused on patients with sinus rhythm at inclusion. Little data are available on the efficacy of CRT in patients with atrial fibrillation (AF), while AF has a high prevalence (20-40%) among patients receiving CRT. This review focuses on the detrimental effect of AF on CRT response and discusses management of patients with AF during CRT. Uncertainty remains as to which thresholds of AF burden can lead to a reduced response to CRT and every effort should be made in trying to assess and guarantee successful biventricular pacing in patients with AF.