[Effect of a revascularization procedure on functioning of the hibernating myocardium]

Persistent abnormalities of left ventricular wall motion in patients with chronic coronary artery disease can be reversed by successful coronary artery bypass surgery or coronary angioplasty. The identification of hibernating myocardium has therefore important therapeutic and prognostic implications. Echocardiography with low dose dobutamine infusion can detect viable myocardium in patients with chronic left ventricular dysfunction. We have studied 32 patients with angiographically confirmed coronary artery disease and left ventricular dysfunction. The effect of dobutamine infusion (5 micrograms/kg/min. followed by 10 micrograms/kg/min) on left ventricular function was evaluated before coronary revascularization (PTCA, n = 20); CABGm b = 12) and compared with early period after revascularization (1-7 days) and 6-7 months later. Before revascularization 226 segments were hypokinetic, akinetic or dyskinetic, improvement was observed in 122 segments during dobutamine echocardiography. Mean (+/- SD) segment score indexes were 2.50 +/- 0.17 at baseline, 2.04 +/- 0.19 (p < 0.001) after dobutamine infusion, 2.24 +/- 0.25 (p < 0.001) early after and 1.87 +/- 0.25 (p < 0.001) late after revascularization. Sensitivity of dobutamine infusion to predict improvement early and late after revascularization was 84% and 85% respectively, specificity was 85% and 90% respectively. Echocardiography during low dose dobutamine infusion is save and accurate method for identifying of hibernating myocardium and predicts early and late reversibility of wall motion in selected patients with coronary artery disease and chronic left ventricular dysfunction.