Clinical importance of new-onset atrial fibrillation after cardiac resynchronization therapy

BackgroundData on the occurrence and implications of new-onset atrial fibrillation (AF) following cardiac resynchronization therapy (CRT) are scarce. We studied the incidence of new onset AF in CRT-defibrillator (CRT-D) recipients. The influence of new-onset AF on echocardiographic response to CRT and the rate of adverse events also were evaluated.ObjectiveThe purpose of this study was to assess the incidence and implications of new-onset AF following CRT.MethodsThe study population consisted of 223 consecutive patients with no history of AF. New-onset AF was defined as atrial high-rate episodes >180 bpm for more than 10 minutes/day as detected by the device. Echocardiography was performed at baseline and after 6 months of biventricular pacing. Long-term events included implantable cardioverter-defibrillator therapy for ventricular arrhythmias, hospitalization for heart failure, and all-cause mortality.ResultsFifty-five (25%) patients developed new-onset AF during mean follow-up of 32 ± 16 months. When compared to the patients who maintained sinus rhythm during follow-up, patients who developed AF showed less left ventricular (LV) reverse remodeling (ΔLV end-systolic volume 37 ± 53 vs >19 ± 37 mL, P <.05) and less improvement in LV function (ΔLV ejection fraction 6.7% ± 8.9% vs 3.5% ± 10.3%, P <.05) . Importantly, patients who developed AF experienced more appropriate ICD shocks for ventricular arrhythmias, more inappropriate shocks, and more hospitalizations for heart failure.ConclusionRecipients of CRT-D who develop new-onset AF show less echocardiographic response to CRT and more cardiac adverse events during long-term follow-up.