Effect of short-acting beta blocker on the cardiac recovery after cardiopulmonary bypass

It has been well documented that early administration of beta-adrenergic antagonist during CPB or within 10 minutes after releasing of aortic clamp contributes to left ventricular function [1,2]. Also, cardioplegia contained esmolol, an ultra-short acting (9-minute half-life) cardioselective beta blocker [3], has cardioprotection in animal model and clinical patients [4-7]. However few studies have investigated beta-adrenergic antagonist on the details of the cardiac recovery and rhythm during CPB. In this study, we therefore investigated the effect of esmolol on the cardiac recovery in rheumatic heart surgeries.The study protocol followed the Declaration of Helsinki and was approved by the Ethics and Research Committee of Nanjing Medical University (Nanjing, P.R. China). The study was performed in a prospective randomized manner after all the patients signed written informed consents.60 rheumatic heart disease patients undergoing elective single mitral valve replacements were enrolled in our study. Patients were randomly assigned to two groups by a computer program. 30 patients received esmolol (Qilu Pharmacy, China)1 mg/kg prior to removal of the aortic clamp, while 28 received the same volume of saline. 2 patients were excluded because of cardiopericarditis. The cardiac recovery of patients was assessed on the basis of:(1) the heart auto re-beat ratio (the heart beat returns spontaneously without ventricular fibrillation or a temporary pacemaker); (2) the recovery time (time from reperfusion to steady heart beat); (3) the ratio of atrial fibrillation during weaning; (4) Ventricular fibrillation after primary re-beat (5) heart rate after steady re-beat; (6) heart rate 10 minutes after re-beat, and (7) temporary peri-operative pacemaking, (8) vasoactive drug use during weaning from CPB. We also recorded the bypass associated time.The data were analyzed with the software SPSS 11.0. The quantitative data were expressed as mean ± SD, and the difference was compared us