Objective To evaluate the response and potential reasons of cardiac resynchronization therapy (CRT) in patients with refractory congestive heart failure (CHF) and atrial fibrillation (AF).Methods Five cases of CHF complicated by AF from March 2003 to March 2007 were enrolled.Among them,there were four cases of dilated cardiomyopathy and one case of ischemic myopathy,with NYHA class Ⅲ-Ⅳ.Left ventricular leads were successfully implanted via coronary sinus in 4 patients.It failed in one case,and then,the case was subjected to pacing at two sites of right ventricle,including high septum aspect of right ventricle and apex.Results The average follow-up duration was 12±13 months.At the final follow-up visit,improvements in symptoms,quality of life and exercise tolerance in all patients were observed,and NYHA class increased by 0+-2 grades.The average percentage of biventricular pacing (BiV-p) was (90±9)%.Case 2,4,and 5 suffered ventricular premature beat frequently,with lower percentage of BiV-p (77%-83%).The percentage of BiV-p in case 2 increased from 83% to 95% after administration of amiodarone.All 5 patients died within 1-33 months after implantation,among which,3 died of deterioration of heart failure and 2 of ventricular arrhythmias.Conclusion CRT is effective in treating CHF patients complicated by AF.High percentage of BiV-p is one of the key factors influencing the response of CRT in this group of patients.For CHF patients with AF,CRT may need to be considered in the earlier stage of CHF.CRT-defibrillator treatment may be more suitable in some of these patients.?更多