Efficacy of serial electrical cardioversion therapy in patients with chronic atrial fibrillation after valve replacement and implications for surgery to cure atrial fibrillation.

Chronic atrial fibrillation (AF) occurs often in the setting of mitral and aortic valve disease. Eventually, these patients undergo valve replacement which improves cardiac function but does not prevent AF. This study investigates which patient may benefit from additional surgery for the cure of AF performed in combination with valve surgery. Seventy-four patients were retrospectively included from our prospective database of patients referred for serial cardioversion therapy between 1986 and 1993. All these patients had chronic AF after valve replacement. After the first electrical cardioversion, patients did not receive antiarrhythmic drugs. Relapses were managed by repeated cardioversions, and then antiarrhythmic drugs were instituted. After a median follow-up of 7 years (range 1.3 to 23), 39 patients had intractable AF. Multivariate analysis revealed that patients with a history of chronic AF before surgery (risk ratio 5.4, confidence intervals 2.5 to 11.3, p = 0.0001) had a poor arrhythmia outcome. In addition, Kaplan-Meier survival analysis demonstrated a lower success rate (p = 0.0017) in patients with mitral valve disease than in those with aortic valve disease. Congestive heart failure (41% vs 6%, p = 0.0007) and cardiovascular mortality (23% vs 9%, p = 0.09) were seen most often in patients with an unsuccessful cardioversion strategy. Thus, patients scheduled for mitral valve surgery with a history of chronic AF should be considered candidates for additional surgery for AF concomitantly performed during valve surgery.