Echocardiographically detected dyskinesis, myocardial infarct size, and coronary risk region relationships in reperfused canine myocardium.
After permanent coronary artery occlusion, the extent of two-dimensional echocardiographically detected dyskinesis correlates well with infarct size. Reperfusion after coronary artery occlusion decreases infarct size; however, contractile function of myocardium salvaged in this way may remain depressed for several weeks. The purpose of this study was to explore the relationship between echocardiographically detected dyskinesis and infarct size in reperfused myocardium. We hypothesized that after transient coronary artery occlusion, the relationship between dyskinesis and infarct size would be altered because of the prolonged depression of contractile function after reperfusion so that dyskinesis would not predict infarct size. We also wanted to explore two related questions: (1) Does inotropic stimulation of reperfused myocardium result in improved systolic function in segments that are dysfunctional but not necrotic? (2) Does the relationship between infarct size and coronary risk region, which is linear in myocardium subjected to permanent coronary occlusion, remain linear in myocardium subjected to a sequence of occlusion and reperfusion? Thirty-seven sedated dogs with preplaced circumflex occluders underwent 1 or 2 hr of coronary artery occlusion, then 2 or 10 days of reperfusion. The percentage of the left ventricle that was dyskinetic was estimated from short-axis two-dimensional echocardiograms at the chordal and papillary muscle level obtained at control, after 1 or 2 hr of occlusion, after 20 min of reperfusion, and after 2 or 10 days of reperfusion. At 2 or 10 days of reperfusion, echocardiograms were also obtained during infusion of dobutamine. Area at risk was determined from postmortem barium-gelatin angiography and infarct size was determined at pathologic examination. We found a significant linear correlation between infarct size and risk region size in reperfused myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)
- Copyright © 1985 by American Heart Association