ASSESSMENT OF VIABLE MYOCARDIUM BY DOBUTAMINE TRANSESOPHAGEAL ECHOCARDIOGRAPHY AND COMPARISON WITH F-18 FLUORODEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY

Objectives. The aim of this study was to assess whether dobutamine tra nsesophageal echocardiography can identify viable myocardium in patien ts with chronic myocardial infarction. Background. Experimental and cl inical studies have shown that dobutamine can recruit a contraction re serve in postischemic viable but akinetic segments, indicating that do butamine-induced functional recovery is a potential ultrasound marker of myocar- dial viability. Methods. Forty patients underwent rest and dobutamine trans- esophageal echocardiography (dobutamine 5, 10 and 20 mu g/kg body weight per min) and fluorine-18 (F-18) fluorodeoxyglucos e positron emission tomography at rest. Three representative short-axi s tomograms and a transverse four chamber-view were used for wall moti on and F-18 fluorodeoxyglucose uptake analysis in corresponding myocar dial regions. A basally asynergic segment was considered viable by tra nsesophageal echocardiography if dobutamine induced systolic wall moti on could be observed. Viability by positron emission tomography was de fined as F-18 fluorodeoxyglucose uptake greater than or equal to 50% o f the maximal uptake in a region with normal wall motion by left ventr iculography. Results. Functional recovery within the infarct region wa s found in 21 (53%) of 40 patients during dobutamine infusion. Infarct region-related viability by F-18 fluorodeoxyglucose uptake was diagno sed in 25 (63%) of 40 patients, yielding a diagnostic agreement betwee n both techniques in 90% of patients. In 210 (89%) of 235 akinetic seg ments at rest, data on myocardial viability were concordant by the two techniques. The positive and negative predictive accuracy of dobutami ne transesophageal echo cardiography for viability defined by F-18 flu orodeoxyglucose uptake was 81% and 97%, respectively. Such uptake was significantly different (p < 0.001) between segments remaining akineti c (mean +/- SD 45 +/- 9%) during dobutamine infusion and segments with a dobutamine-induced contraction reserve (68 +/- 11%). Conclusions. D obutamine transesophageal echocardiography provides a promising low co st and widely available approach to unmask myocardial viability in pat ients with chronic myocardial infarction, and results compare favorabl y with those of F-18 fluorodeoxyglucose positron emission tomography.