The primary aim of the study is to determine if patients with permanent AF who meet conventional criteria for CRT and undergo AVJ ablation have reduced ventricular remodeling (i.e. echocardardiographic improvement of LV end systolic volume), a potent marker of subsequent clinical deterioration, compared to patients who do not undergo AVJ ablation. This study is designed to test feasibility of enrollment and short-term improvement in surrogate endpoints, with anticipation of a full-scale large randomized clinical trial using hard outcome events if this phase is promising.