ECHOCARDIOGRAPHY DURING INFUSION OF DOBUTAMINE FOR IDENTIFICATION OF REVERSIBLE DYSFUNCTION IN PATIENTS WITH CHRONIC CORONARY-ARTERY DISEASE

Objectives. The aim of this study was to test whether the contractile response of akinetic myocardium to low dose dobutamine is useful for d etecting myocardial viability in patients with coronary artery disease and persistent left ventricular dysfunction. Background. In some pati ents with chronic coronary artery disease, persistent abnormalities of left ventricular wall motion can be reversed by successful coronary a rtery bypass surgery. Thus, identification of potentially reversible d ysfunction has important therapeutic and prognostic implications. Echo cardiography during infusion of low dose dobutamine can detect viable myocardium in patients after thrombolytic therapy. However, there is n o detailed information on the use of this method in patients with chro nic left ventricular dysfunction without reperfusion. Methods. We stud ied 33 selected patients with angiographically proved coronary artery disease and persistent left ventricular dysfunction. The effect of dob utamine infusion (5 mu g/kg body weight per min, followed by 10 mu g/k g per min) on left ventricular wall motion was evaluated by transthora cic echocardiography before coronary artery bypass grafting and compar ed with that obtained immediately after the operation (evaluated by in traoperative epicardial echocardiography) and both 2 weeks and 3 month s later. Left ventricular wall motion was analyzed qualitatively by di viding the left ventricle into 16 segments, and a score was assigned t o each region. Results. Before coronary artery bypass surgery, 314 seg ments were akinetic. Of these, 183 became normokinetic immediately aft er revascularization, and 15 became hypokinetic. Dobutamine infusion w as able to predict improvement in 178 of the 205 segments that recover ed function after revascularization (sensitivity 86.8%) and to identif y 89 of the 109 segments that did not recover postoperatively (specifi city 81.6%). Mean (+/-SD) segment scores were 2.24 +/- 0.35 at baselin e, 1.49 +/- 0.34 (p < 0.001) after dobutamine infusion, 1.51 +/- 0.38 (p < 0.001) immediately after and 1.51 +/- 0.38 (p < 0.001) 2 weeks af ter coronary artery bypass and 1.55 +/- 0.37 (p < 0.001) at 3 month fo llow-up. Conclusions. Echocardiography during infusion of low dose dob utamine is a safe and accurate method for identifying reversible dysfu nctioning myocardium and predicts early reversibility of wall motion a fter surgical revascularization in selected patients with coronary art ery disease with chronic left ventricular dysfunction.