Recovery of myocardial function. The ultimate target of coronary revascularization

Recovery of myocardial contraction represents an important target of coronary revascularization and the preoperative recognition of viable akinetic (hibernating) myocardium is a crucial point of the preoperative investigation of patients with chronically depressed left ventricular function. In 14 patients dobutamine infusion during echocardiography was utilized to evoke the contractile reserve retained by viable akinetic segments. Redistribution of thallium(Tl)-201 after the rest injection was also used to assess the viability of akinetic areas. The wall motion response to dobutamine infusion predicted immediate postoperative improvement in 85 of 93 segments (sensitivity 91.3%) and identified 25 of the 32 segments which did not exhibit early postoperative improvement (specificity 78.1%). Rest redistribution of Tl-201 demon-strated high sensitivity (93.0%) but low specificity (43.7%) for predicting the early recovery of regional wall motion. When late recovery was also considered, the specificity of this method increased to 64.0%. Rest distribution of Tl-201 identifies viability which is not necessarily associated with the early recovery of function postoperatively. When the echo-dobutamine test is positive, on the other hand, the recovery of function usually occurs immediately after revascularization and the operative risk is expected to be low even in the presence of severely compromised left ventricular function.