EARLY EFFECTS OF CORONARY-ARTERY BYPASS-SURGERY AND COLD CARDIOPLEGICISCHEMIA ON LEFT-VENTRICULAR DIASTOLIC FUNCTION - EVALUATION BY COMPUTER-ASSISTED TRANSESOPHAGEAL ECHOCARDIOGRAPHY

Objective: Although left ventricular (LV) systolic function undergoes a temporary decrease after cardiopulmonary bypass (CPB) in patients un dergoing coronary artery bypass grafting (CABG), data on the effects o f CABG and cardioplegic arrest on LV diastolic function are contradict ory. The objective of the present study was to further evaluate the ef fects of CABG and CPB on LV diastolic function. Design: A prospective study. Setting: A multi-institutional investigation at a university ho spital. Participants: 20 patients on beta-receptor antagonists, schedu led for CABG and with a preoperative ejection fraction over 0.5. Inter ventions: Central hemodynamic measurements, transesophageal LV short-a xis images, and mitral Doppler flow profiles were obtained before and after volume loading that in turn was performed both before surgical i ncision and after weaning from CPB. Measurements and Main Results: Hea rt rate, cardiac output, and peak atrial filling velocity increased: s ystemic vascular resistance decreased; whereas stroke volume, LV area ejection fraction, deceleration rate and slope of early diastolic fill ing, time-velocity integral of early diastolic filling, and the ratio between early and atrial peak filling velocity were unchanged post-CPB compared with pre-CPB. LV end-diastolic stiffness that was calculated for each patient pre CPB and post-CPB using the formula: P = Be(S*A) , where P is the LV filling pressure and A is the end-diastolic short- axis area, was unchanged post-CPB compared with pre-CPB. Conclusions: Both the active and passive components of LV diastolic function are we ll maintained shortly after CABG and cardioplegic arrest in patients w ith a good preoperative systolic LV function. Copyright (C) 1996 by W. B. Saunders Company