SIGNIFICANCE OF ELECTROCARDIOGRAPHIC ST ELEVATION DURING CORONARY-ARTERY BYPASS-SURGERY

The aim of this study was to determine the significance of new electro cardiographic (ECG) ST elevation during coronary artery bypass surgery . Multilead ECGs were recorded intraoperatively approximately every 3 min on 105 patients. Cases of new ST elevation were divided into ische mic and those considered to be due to nonischemic causes such as cooli ng during cardiopulmonary bypass (CPB), defibrillation, new cardiac co nduction abnormalities, and pericarditis. The myocardial fraction of c reatine kinase (CK-MB) greater-than-or-equal-to 25 IU/L was considered to be indicative of myocardial injury. Both patients who had ischemic ST elevation prior to CPB and all seven patients who had ST elevation in temporal association with the administration of protamine had peak CK-MB greater-than-or-equal-to 25 IU/L. One patient with peak CK-MB g reater-than-or-equal-to 25 IU/L did not have ST elevation and was cons idered to have injury during CPB. Two of these ten patients had Q wave myocardial infarctions (MIs). For the detection of patients with peak CK-MB greater-than-or-equal-to 25 IU/L, the sensitivity of ischemic S T elevation was 90% and the specificity was 100%. A history of MI prio r to surgery and a history of Type I diabetes were associated with pea k CK-MB greater-than-or-equal-to 25 IU/L (P < 0.05).