Resynchronization therapy in patients with atrial fibrillation: What are the results?

Cardiac resynchronization therapy (CRT) is an established treatment for heart failure (HF) with left ventricular (LV) dysfunction and contraction dyssynchrony associated with intraventricular conduction disturbance, particularly complete left bundle branch block. In CARE-HF, the largest published study, in 813 patients and with a mean follow-up of 29 months, there was a reduction in the primary endpoint (death from any cause or hospitalization for a major cardiovascular event) from 55% in the control group to 39% in the CRT group (hazard ratio 0.63, p<0.001) and in overall mortality from 30% to 20% (hazard ratio 0.64, p<0.002). Compared to medical therapy, CRT also reduced end-systolic volume and severity of mitral regurgitation, increased LV ejection fraction (LVEF), and improved symptoms and quality of life. These findings, confirmed in various studies and meta-analyses, led medical societies to classify CRT as a class I recommendation, level of evidence A.