Preservation of left ventricular function during coronary artery bypass graft surgery.

Effects of hypothermic potassium cardioplegia on left ventricular performance and myocardial damage were assessed in 35 patients undergoing coronary artery bypass surgery. Hemodynamic data and enzymatic evidence of left ventricular ischemic damage were examined and compared in the immediate postoperative period. Left ventricular stroke work index showed a significant depression during the first hour with gradual recovery and a significant increase after 24 h. Myocardial specific isoenzyme creatine kinase (CK-MB) showed a very good nonlinear relationship with stroke work index within the whole range, whereas lactate dehydrogenase isoenzyme (LDH-I) had no relationship with the stroke work index. There was a high incidence of transient postoperative arrhythmias and electrical activity took a long time to stabilize. Left ventricular ultrastructure was generally well preserved. The results of this study demonstrate adequate structural and functional preservation of left ventricle by hypothermic potassium cardioplegia.