Incidence, predictors, and evolution of conduction disorders and atrial arrhythmias after contemporary mitral valve repair.

BACKGROUND Conduction disorders (CD) and atrial arrhythmias (AA) in the postoperative period of cardiac surgery impede prompt clinical recovery and prolong hospitalization. Mitral valve repair (MVR) has become the treatment of choice for patients with significant valvular regurgitation, but information on CD and AA in this population is scarce. METHODS Records of consecutive patients undergoing MVR at a single center were reviewed. Patients with a preoperative pacemaker, CD, prior cardiac surgery or concomitant MVR were excluded. A total of 290 patients were included in the final analysis. Electrocardiograms pre andpost-operatively were analyzed for CD and AA. RESULTS CD occurred in 69 (23.7%) patients: 47 (16.2%) had first degree atrio-ventricular block (AVB), 10 (3.4%) had Mobitz I, 3 (1.03%) had Mobitz II, and 9 (3.1%) complete AVB. Only 6 (2.0%) patients required pacemakers. Univariate predictors of AVB were age, preexisting right bundle branch block (RBBB), mitral valve ring size, and bypass time. The only multivariate predictors of AVB were bypass time and preexisting RBBB (OR 3.23 and 1.98, respectively). The most common AA was atrial fibrillation 13.1% (38 patients) followed by atrial flutter 2.7% (8 patients). Multivariate predictors of AA were age and left atrial size (OR 1.85 and 4.2, respectively). Length of stay in patients with CD or AA was prolonged 2.2 ± 2 days compared to controls (p < 0.05). CONCLUSIONS In this large sample of patients undergoing MVR, we found that bypass time and preexisting RBBB were independent predictors of CD; age and left atrial size were independent predictors of AA.