Junctional AV Ablation in CRT-D: JAVA-CRT

Inclusion Criteria: * Optimal pharmacologic therapy is defined by published guidelines from the American Heart Association and the American College of Cardiology * Initial implantation of CRT-D or prior implantation of CRT-D within one year * Ischemic or nonischemic cardiomyopathy * LVEF ≤ 35% * NYHA class II-IV (ambulatory) * QRS ≥ 120 ms for LBBB and ≥ 150 ms for non-LBBB patients * Continuous AF \> 3 months when no further efforts to restore sinus rhythm are feasible or pursued Exclusion Criteria: * Ventricular rate \> 110 bpm at rest despite maximal medical therapy * Ventricular rate \< 50 bpm at rest * Heart block/symptomatic bradycardia that necessitates permanent pacing * Acute coronary syndrome or coronary artery bypass surgery within 12 weeks * Severe aortic or mitral valvular heart disease * Prior AVJ ablation * Any medical condition likely to limit survival to \< 1 year * Patients with ACC/AHA Stage D refractory Class IV symptoms listed for transplant or requiring inotropic support * Contraindication to systematic anticoagulation * Renal failure requiring dialysis * AF due to reversible cause e.g. hyperthyroid state * Pregnancy * Participation in other clinical trials that will affect the objectives of this study * History of non-compliance to medical therapy * Inability or unwillingness to provide informed consent * Patients with short-lived AF or those in sinus rhythm are ineligible