Atrioventricular block in the postoperative period of heart valve surgery: incidence, risk factors and hospital evolution.

ABSTRACT

INTRODUCTION: Disturbances of the cardiac conduction system are potential complications after cardiac valve surgery. OBJECTIVES: This study was designed to investigate the association between perioperative factors and atrio-ventricular block, the need for temporary cardiac artificial pacing and, if necessary, permanent pacemaker implantation after cardiac valve surgery. METHODS: Retrospective analysis of the Cardiac Surgery Database - Hospital São Lucas/PUCRS. The data are collected prospectively and analyzed retrospectively. RESULTS: Between January 1996 and December 2008 were included 1102 valve surgical procedures 718 aortic valves (65.2%), 407 (36.9%) mitral valve and 190 (17.2%) coronar artery bypass grafting combined with valve repair and 23 (2.1%) aortic and mitral combined surgery. 187 patients (17%) showed clinical and electrocardiographic pattern of atrio-ventricular block requiring artificial temporary pacing. Of these, 14 patients (7.5%) required permanent pacemaker implantation (1.27% of the total valve surgery patients). Multivariate analysis showed association of the incidence of atrio-ventricular block and temporary pacing with mitral valve surgery (OR 1,76; CI 95% 1.08-2.37; P = 0.002), implantation of bioprosthetic devices (OR 1.59; CI 95% 1.02-3.91; P = 0,039), age over 60 years (OR 1.99; CI 95% 1.352.85; P < 0.001), prior use of anti-arrhythmic drugs (OR 1.86; CI 95% 1.04-3.14; P = 0.026) and previous use of b-blocker (OR 1.76; CI 95% 1.25-2.54; P = 0.002). Remarkably the presence of atrio-ventricular block did not significantly show association with increased mortality, but significantly prolonged (P < 0.0001) hospital length-of-stay and, therefore, hospital costs. CONCLUSIONS: Our study presents a group of predictive factors referring to a specific patient profile by which high risk of atrio-ventricular block and the need of temporary cardiac pacing after cardiac valve surgery it is determined.