Cardiac resynchronization therapy in patients with chronic atrial fibrillation.

Heart failure (HF) and atrial fibrillation (AF), 2 of the most common cardiovascular disorders, often coexist in the same patient, as 1 condition can lead to the other. The best approach to AF management in patients with HF is currently under investigation, but there seems to be an abundance of evidence in support of cardiac resynchronization therapy (CRT) in this group of patients. In addition, CRT is emerging as a superior option to stand-alone right ventricular pacing in patients with structural heart disease. However, in patients with AF, an adequate rate control is critical for this therapy to be highly effective. As control of the ventricular response can be difficult to achieve in many of those patients, often a nonpharmacologic intervention is required, such as ablation of the atrioventricular node to create heart block. The definitive role for CRT with or without atrioventricular nodal ablation in patients with AF and HF is yet to be studied in large, well-designed, randomized, controlled clinical trials.