Influence of Preoperative Atrial Fibrillation on Late Results of Mitral Repair: Is Concomitant Ablation Justified?

Background: There is considerable interest in atrial fibrillation (AF) ablation during cardiac operations, but there are few studies addressing the impact of preoperative AF on late outcome of surgery. We therefore investigated AF prevalence in nonrheumatic mitral regurgitation and its effect on late survival and morbidity after repair. Methods: From 1993 through 2002, 36% of 2,821patients with mitral regurgitation had preexisting AF. A cohort of these was matched with controls in sinus rhythm (SR) for age, gender, and ejection fraction. Follow-up was by questionnaire. Outcomes were compared between 231AF and 229 SR patients, and patients with different types of preoperative AF. Results: Patients with preoperative AF were more symptomatic and frequently had cardiomegaly, heart failure, and higher mean pulmonary artery systolic pressure. Operative mortality was higher for AF patients (2% vs 0, p = 0.05). More AF patients had late adverse cardiac events and stroke (63% vs 31%, p < 0.0001). Five- and ten-year survival was, respectively, 95% and 88% for SR patients compared with 90% and 70% (p = 0.01) for the AF group. By multivariate analysis, preoperative AF was not a predictor of long-term survival but was an independent risk factor for late adverse cardiac events and stroke. Conclusions: Preoperative AF is a marker for increased surgical risk of mitral regurgitation repair, and a risk factor for late adverse cardiac events and stroke. Although the independent contribution of AF to late survival is uncertain, preoperative AF increases postoperative morbidity independently; therefore, corrective intervention would be expected to benefit patients in this regard.