Pre-operative atrial fibrillation as the key determinant of outcome of mitral valve repair for degenerative mitral regurgitation.

AIMS: To examine the impact of pre-operative atrial fibrillation (AF) on the outcome of mitral valve repair (MVR) for degenerative mitral regurgitation (MR). METHODS AND
RESULTS: Among 392 patients with moderate to severe MR who underwent MVR between 1991 and 2002, 283 patients with isolated degenerative MR were followed for 4.7+/-3.3 years. Of 27 deaths, nine were due to cardioembolic events and four were due to left ventricular (LV) dysfunction. When compared with patients with pre-operative AF, those with sinus rhythm (SR) had better survival (96+/-2.1 vs. 87+/-3.2% at 5 years, P=0.002) and higher cardiac event-free rates (96+/-2.0 vs. 75+/-4.4% at 5 years, P<0.001). In patients with pre-operative SR, observed and expected survival were similar (P=0.811). Cox multivariable regression analysis confirmed AF [P=0.027, adjusted hazard ratio (AHR) 2.9] and age as independently predictive of survival, and AF (P=0.002, AHR 3.1), New York Heart Association Class, and LV fractional shortening as independently predictive of cardiac event.
CONCLUSION: Death due to LV dysfunction was not frequent and cardioembolic events due to AF were the leading cause for cardiac death. Pre-operative AF became a strong independent predictor of survival and morbidity. Patients with pre-operative SR had excellent prognosis. The benefits of preventing cardioembolic events due to AF validate the indication of MVR for patients with high risk for AF.