Bypass graft surgery in severe left ventricular dysfunction
The efficacy of myocardial revascularization in improving left ventricular function and prognosis in patients with severe left ventricular dysfunction is controversial. This study was designed to determine the effect of coronary bypass graft surgery on rest and exercise ventricular function in patients with left ventricular dysfunction. Nineteen patients with coronary artery disease who had left ventricular ejection fractions of 40% or less were studied at rest and during maximal upright bicycle exercise using first-pass radionuclide angiography to measure ejection fraction, wall motion and end-diastolic volume pre- and postoperatively. These same patients had repeat coronary arteriography 10-14 days postoperatively. In addition, 15 presumably healthy, young male volunteers were studied by the same technique to serve as controls and illustrate the normal response to upright exercise. The normal response, as previously demonstrated, was maintained or improved ventricular function with exercise; i.e., ejection fraction does not decrease, regional wall motion disorders do not appear and significant left ventricular dilatation does not occur. In contrast, preoperatively, the patients with coronary artery disease showed the following: 14 of 19 had a decrease in ejection fraction, 16 developed regional wall motion disorders and seven had marked left ventricular dilatation. After myocardial revascularization, the resting ejection fractions improved. With exercise, 16 of the 19 patients demonstrated a response toward normal, with a maintenance or increase in ejection fraction and no deterioration of regional wall motion. One other patient showed marked ventricular dilatation with exercise. Postoperative coronary arteriography revealed unsuccessful or incomplete revascularization in three of the four patients with an abnormal response to symptom-limited maximal exercise. The data suggest that left ventricular function at rest and during exercise can be improved by myocardial revascularization in the patient with coronary artery disease and severe left ventricular dysfunction.