Impact of atrial fibrillation on efficacy of cardiac resynchronization therapy in patients with severe heart failure

The aim of the study was to evaluate impact of atrial fibrillation on efficacy of cardiac resynchronization therapy (CRT) in patients with severe heart failure. The study comprised 110 patients (56 women) aged 47.7±10.9 years with NYHA functional class III chronic heart failure (CHF), main diagnosis of dilated cardiomyopathy (DCM), and registered permanent form of atrial fibrillation (AF). The QRS width varied from 146 ms to 240 ms (average 183±32 ms); left ventricular ejection fraction (EF) was 30.1±3.8%; end diastolic volume (EDV) was 272.4±49.8 mL; and 6-minute walk distance was 247.8±57.3 m. Optimal drug therapy for CHF was inefficacious in these patients during three to six months. All patients were implanted with CRT device. Follow up examination in the presence of biventricular stimulation was conducted after 36 months of therapy. The analysis of the results of 36-month-long CRT demonstrated that sinus rhythm spontaneously restored in 84 patients (76.4%) who had AF and inefficacious antiarrhythmic therapy before the beginning of CRT. During three years of the study, EF increased in this patients’ group by 18% from 29.0±3.8% to 42.5±4.2% (р