Dissociation between two-dimensional echocardiographic left ventricular wall motion and myocardial salvage in early experimental acute myocardial infarction in dogs

This study was designed to evaluate whether the effects of coronary reperfusion with or without a pharmacologic agent could be detected in the early hours after infarction by 2-dimensional (2-D) echocardiography applied in a manner analogous to its clinical use. Proximal left anterior descending coronary occlusion was performed in 24 dogs, and the dogs were then randomized into 3 groups. In group 1 (n = 8), coronary occlusion was maintained for 6 hours; in group 2 (n = 8), coronary occlusion was maintained for 2 hours and was followed by 4 hours of reperfusion; in group 3 (n = 8), 2 hours of coronary occlusion were followed by 4 hours of reperfusion but methylprednisolone (30 mg/kg intravenously) was also administered 15 minutes after coronary occlusion. At 6 hours, 2-D images were obtained through the closed chest wall and the percentage of the left ventricular wall motion abnormalities was determined at 4 short-axis levels. The mass at risk was defined by in vivo Monastral blue injection and infarction by triphenyltetrazolium chloride staining. The mass of necrosis was 74 +/- 4% (mean +/- standard error of the mean) of the mass at risk in group 1 and was smaller in groups 2 and 3, 44 +/- 6% and 35 +/- 4%, respectively (p less than 0.01). Percent necrosis of the left ventricle was 22 +/- 3% in group 1, 15 +/- 3% in group 2 (difference not significant) and 10 +/- 2% in group 3 (p less than 0.05 vs group 1).(ABSTRACT TRUNCATED AT 250 WORDS)