Enoximone coupled to very low dose dobutamine echocardiography detects myocardial viability in akinetic and dyskinetic post-myocardial infarcted areas

Dobutamine and enoximone stimulate independently inotropic reserve by incre asing intracellular cyclic adenosine monophosphate. The potential of enoxim one (0.75 mg/kg body weight over 10 minutes) followed by very low dose (2.5 mu g/kg/min) dobutamine echocardiography to predict recovery of ventricula r function in akinetic and dyskinetic postinfarcted areas was studied. We e nrolled 22 patients with previous Q-wave myocardial infarction and regional wall motion abnormalities related to left anterior descending arterial dis ease, left ventricular election fraction <40%, and all scheduled for myocar dial revascularization. A 10 mu g/kg/min dobutamine test was performed 48 h ours before the study protocol. Test images obtained at peak of pharmacodyn amic effects were compared with those obtained at 4 months after myocardial revascularization, We used a 16-segment ventricular model and a 5-grade sc oring system. Resting regional myocardial dysfunction graded greater than o r equal to 2 was present in 267 of 352 segments evaluated. Contractile rese rve (decrease in testing wall motion score greater than or equal to 2 grade s) at peak effect of enoximone infusion was present in 34 of 112 severely h ypokinetic, 42 of 117 akinetic, and 14 of 38 dyskinetic segments. The inotr opic reserve evaluated after very low dose dobutamine was observed in 34 of 112 severely hypokinetic, 49 of 117 akinetic, and 20 of 38 dyskinetic segm ents. After revascularization, recovery of function was observed in 31 of 1 12 severely hypokinetic, 49 of 117 akinetic, and 21 of 38 dyskinetic segmen ts. Overall, there was a significant correlation between absolute score cha nges of segments which were abnormal at baseline (n = 267) to enoximone pea k effects (r = 0.49, p <0.001) to predict absolute changes after revascular ization; after dobutamine there was progress toward identify (r = 0.62, p < 0.001) and the difference wets significant among correlation slopes of dobu tamine alone, enoximone alone, and enoximone plus very low dose dobutamine echocardiography (0.45 +/- 0.04, 0.51 +/- 0.04, and 0.63 +/- 0.04, respecti vely, F = 5.25, p = 0.005). Therefore, enoximone followed by very low dose dobutamine may assess myocardial viability of postinfarcted akinetic and dy skinetic areas. This test may be useful when evaluating patients with more severe cardiac failure and/or life-threatening arrhythmias. (C) 1999 by Exc erpta Medico, Inc.