Managing atrial fibrillation in the CRT patient: controversy or consensus?

The cumulative incidence of new onset atrial fibrillation (AF) in patients undergoing cardiac resynchronization therapy (CRT) is substantial, exceeding 25% in multiple recent studies. Although AF patients undergoing CRT show improved echocardiographic parameters, functional status, and quality of life in, they benefit to a lesser degree than do patients in normal sinus rhythm. They also exhibit a trend toward increased mortality. Understanding the barriers to response from CRT among AF patients is critical to addressing the needs of growing populations of patients with AF and HF. Foremost among these are suboptimal biventricular pacing, often characterized by fusion or pseudo-fusion complexes, leading to inefficient CRT delivery. Furthermore, AF increases the risk of inappropriate shocks, which lead to substantial psychiatric morbidity, increased risk of heart failure hospitalization, and may also increase mortality. Assiduous rate control is reasonable for all AF patients receiving CRT, but there is a paucity of data regarding specific antiarrhythmic drug therapy recommendations. For patients with permanent AF and severe symptoms, atrioventricular junction ablation appears effective in improving response by ensuring biventricular capture and reducing implantable cardioverter-defibrillator shock burden in selected patients. Catheter-based techniques such as pulmonary vein isolation appear more attractive and in the future may offer further advantages and lower risks, particularly for patients with paroxysmal AF.