Clinical Outcomes and Characteristics with Dofetilide in Atrial Fibrillation Patients Considered for Implantable Cardioverter-Defibrillator.

Background - Dofetilide is one of the only anti-arrhythmic agents approved for atrial fibrillation (AF) in patients with reduced left ventricular ejection fraction (LVEF). However, post-approval data and safety outcomes are limited. In this study, we assessed the incidence and predictors of LVEF improvement, safety, and outcomes in AF patients with LVEF ≤ 35% without prior implantable cardioverter defibrillator (ICD), cardiac resynchronization therapy (CRT), or AF ablation. Methods - An analysis of 168 consecutive patients from 2007 to 2016 was performed. Incidences of adverse events, drug continuation, ICD and/or CRT implantation, LVEF improvement (>35%) and recovery (≥50%), AF recurrence, and AF ablation were determined. Multivariable regression analysis to identify predictors of LVEF improvement/recovery was performed. Results - The mean age was 64±12 years. Dofetilide was discontinued prior to hospital discharge in 46 (27%) because of QT prolongation (14%), torsades de pointe or polymorphic ventricular tachycardia/fibrillation (6% [sustained 3%, non-sustained 3%]), ineffectiveness (5%), or other causes (3%). At 1 year, 43% remained on dofetilide. Freedom from AF was 42% at 1 year, and 40% underwent future AF ablation. LVEF recovered (≥ 50%) in 45% and improved to >35% in 73%. Predictors of LVEF improvement included presence of AF during echocardiogram (odds ratio [OR] 4.22, 95% CI, 1.71 - 10.4, p=0.002), coronary artery disease (OR 0.35, 95% CI, 0.16 - 0.79, p=0.01), left atrial diameter (OR 0.52 per 1 cm increase, 95% CI 0.30 - 0.90, p=0.01), and LVEF (OR per 1% increase, 1.09, 95% CI, 1.02 - 1.16, p=0.006). The C-statistic was 0.78. Conclusions - In patients with LVEF ≤ 35%, who are potential ICD candidates, treated with dofetilide as an initial anti-arrhythmic strategy for AF, drug discontinuation rates were high, and many underwent future AF ablation. However, most patients had improvement in LVEF, obviating the need for primary prevention ICD.