Two-dimensional echocardiographic recognition of myocardial injury in man: Comparison with postmortem studies

Abstract

To assess the accuracy of phased-array two-dimensional echocardiography in detecting, localizing and quantifying myocardial injury in man, the relationship of two-dimensional echocardiographic wall motion abnormalities to morphologic evidence of myocardial infarction was evaluated in 20 autopsied patients. Comparisons were made between independent two-dimensional echocardiographic readings of left ventricular segmental wall motion and morphologic evidence of myocardial injury. Of 15 infarcts, 14 were detected by regional akinesis, dyskinesis or hypokinesis. The relationship between abnormal segmental wall motion and morphologic evidence of myocardial necrosis or fibrosis was significant. Seventy-nine of 88 (90%) of infarcted segments showed abnormal wall motion, although 38 of 82 (46%) of morphologically normal segments also demonstrated wall motion abnormalities. Fifty-eight of 65 segments that showed regional akinesis or dyskinesis were transmurally infarcted. Twenty-five of 38 pathologically normal segments seen by two-dimensional echocardiography as akinetic or dyskinetic were adjacent to scar. Hypokinesis was non-specific (31 segments normal, 21 subendocardial infarction). Normal wall motion excluded transmural infarction (0 of 46 segments), but in one patient was associated with subendocardial injury (nine/42 segments). We assessed circumferential extent of regional akinesis or dyskinesis in blind fashion with a light-pen system, expressed as a percentage of end-diastolic circumference, and compared this with the corresponding cross section of the left ventricle examined pathologically. By linear regression, extent of two-dimensional echocardiographic akinesis or dyskinesis and extent of left ventricular circumference demonstrating morphologic evidence of transmural infarction correlated well: pathologic percent circumference infarcted = 1.14 (two-dimensional echocardiographic percent circumference akinetic/dyskinetic) - 14.48; r = 0.90. Wall motion abnormalities therefore overestimated the amount of myocardial circumference infarcted, possibly because of the proximity of morphologically normal segments to scar or because segments adjacent to the lesions were reversibly ischemic. The results suggest that two-dimensional echocardiographic evidence of regional wall motion abnormality is sensitive in detecting and localizing segmental pathologic myocardial lesions, but overestimates their extent.