Spontaneous conversion of permanent atrial fibrillation into stable sinus rhythm after 17 months of biventricular pacing.

A 68-year-old woman with drug refractory congestive heart failure (NYHA Class III, ejection fraction 35%, moderate to severe mitral regurgitation) and permanent atrial fibrillation uninterrupted for >3 years, underwent implantation of a biventricular pacing system. Seventeen months later, atrial fibrillation spontaneously converted into sinus rhythm, which has been maintained for more than 6 months (to date).