INFLUENCE OF THE PREOPERATIVE SIGNAL-AVERAGED ELECTROCARDIOGRAM ON LEFT-VENTRICULAR FUNCTION AFTER CORONARY-ARTERY BYPASS GRAFT-SURGERY IN PATIENTS WITH LEFT-VENTRICULAR DYSFUNCTION

Patients with ischemic left ventricular (LV) dysfunction often have an improved survival and life quality after coronary artery bypass graft ing (CABG), in part due to an improvement in LV function, A lack of LV election fraction (EF) improvement postoperatively portends a worse p rognosis. Recently, an abnormal preoperative signal-averaged electroca rdiogram (SAECG) in patients with a severely depressed LV election fra ction undergoing elective CABG was shown to be associated with a highe r early and late postoperative mortality. The present study evaluated patients with severe LV dysfunction to identify any relation between a n abnormal preoperative SAECG and postoperative changes in LV function after successful CABG, Forty-five patients with LV dysfunction (LVEF <0.36) scheduled for elective CABG underwent preoperative SAECG and bo th pre- and postoperative LVEF determinations using radionuclide scans . Thirty-one patients in the group had an abnormal preoperative SAECG and 14 patients had a normal preoperative SAECG, Baseline patient char acteristics were similar in both groups and the mean preoperative LVEF was 0.26. Overall, LVEF improved 31% postoperatively with a significa ntly greater benefit noted in the group with a normal baseline SAECG ( 14.9 +/- 5.7-point vs 4.8 +/- 8.5-point increase, p <0.001). All patie nts whose LVEF did not improve or worsened postoperatively had an abno rmal preoperative SAECG. No SAECG measure was altered significantly by the operation. A preoperative SAECG provides information on the posto perative functional recovery of ischemic myocardium. (C)1998 by Excerp ta Medica, Inc.