431 LONG-TERM ATRIO-VENTRICULAR BLOCK FOLLOWING VALVE SURGERY: ELECTROCARDIOGRAPHIC AND SURGICAL PREDICTORS


 
 
 Bradyarrhythmias requiring pacemaker implantation (PM) in patients undergoing valve surgery may occur even after several years. The incidence of PM implantation after valve surgery and its predictors are unclear.
 
 
 
 A retrospective, monocentric, cohort study was conducted. Consecutive patients undergoing valve surgery at the Division of Cardiac Surgery at the Bologna University Hospital from 2005 to 2010 were enrolled. The primary endpoint of the study was to evaluate the incidence of PM implantation in patients undergoing valve surgery, at different follow-up times, and to evaluate the predictors of PM implantation.
 
 
 
 We included 1046 patients (61.8% male, median age 63 years). Of these 735 (70%) reached a 10 year of follow-up and 11.4% required PM implantation. In single valve surgery, mitral interventions had a higher incidence of PM implantation compared to aortic ones, albeit not significantly different (11% vs 8.1%, HR 1.2, IC 95% 0.6-2.1, p=0.590). Among combined surgery, interventions on both atrioventricular valves doubled the risk compared to those performed on aortic and mitral valves (23.1% vs 12%). Moreover, interventions involving both atrioventricular valves independently predicted PM implantation in the long term (HR 2.0, IC 95% 1.1-3.7, p=0.022). Preoperative atrioventricular conduction disease strongly predicted long-term atrio-ventricular block: right bundle branch block with or without left anterior fascicular block (LAFB) was the major predictor (HR 7.2, IC 95% 2.8-19, p<0.001, HR 6.8, IC 95% 3.9-11.7, p<0.001 respectively), followed by left bundle branch block (HR 5.1, IC 95% 2.6-10.3, p<0.001), LAFB (HR 4.2, IC 95% 1.9-8.9, p<0.001) and a non-specific ventricular conduction delay (HR=3.3, IC 95% 1.3-8.4, p=0.012). Age was also predictive, PM implantation probability increasing at each year-age increase (HR 1.02, IC 95% 1.01-1.04, p=0.022)
 
 
 
 Patients undergoing valvular surgery have a continuing risk of atrioventricular block requiring PM therapy late after surgery; combined surgery on atrio-ventricular valves carries the highest risk, while preoperative atrioventricular conduction disease have different risks of AVB at long-term.
