722-1 High Dose Dobutamine Echocardlography Detects Myocardial Viability and Ischemia in Coronary Cardiomyopathy

Abstract

Augmentation of wall motion during low dose ( ≤ 10 meg/kg/min) dobutamine infusion has been utilized to detect myocardial viability in patients with ischemic cardiomyopathy. The utility of high dose (30–50 mcglkg/min) dobutamine infusion to detect viable and compromised myocardium has not been described. Thirty-three patients with ischemic cardiomyopathy (mean EF of 0.33 ± 0.084) had low and high dose dobutamine echocardiograms and positron emission tomography (PET) using N-13 ammonia (NH3) and fluorodeoxyglucose (FOG). Left ventricular wall motion, NH3 and FDG uptake were scored using a 16 segment model. Of 490 interpretable segments, 321 (66%) were abnormal at rest. At low dose 85 (27%) segments augmented of which 80 (94%) were viable by PET. In 15 patients, an additional 32 (10%) abnormal segments augmented at high dose. PET viability was noted in 29 (91%) of these segments. In 18 of 33 patients (55%), 38 segments had stress induced wall motion abnormalities at high dose. Of the 38 segments, 37 (97%) were viable by PET. Angiography showed 34 of these 38 (89%) segments were supplied by an obstructed coronary artery ( ≥ 50% diameter stenosis). 1) The use of higher doses increases the sensitivity of DE to detect viable myocardium. 2) Deterioration of wall motion at peak indicates viable but compromised myocardium supplied by an obstructed coronary artery.