Regional function and perfusion at the lateral border of ischemic myocardium

To determine whether function is depressed in areas of myocardium adjacent to an area of myocardial ischemia, 16 open-chest dogs were studied with both two-dimensional echocardiography and ultrasonic microcrystals. Regional myocardial blood flow was measured with radioactive microspheres during control periods and after coronary arterial ligation. Segments of myocardium adjacent to the area of ischemia were found to have no significant change in transmural blood flow (1.02 ± 0.38 ml/g/min control vs 0.95 ± 0.3 ml/g/min after ligation) or subendocardial flow (1.18 ± 0.41 ml/g/min control vs 1.19 ± 0.37 ml/g/min after ligation). Regional function assessed echocardiographically as percent change in segment area was significantly depressed in these normally perfused adjacent areas (69.5 ± 18.8% control vs 52.5 ± 19.8% after ligation; p < .01). There was a significant relationship between proximity to border of infarction and degree of adjacent dysfunction (r = .50, p < .01 for echocardiography; r = .70, p < .01 for ultrasonic microcrystals). It is concluded that systolic performance is depressed in nonischemic myocardium directly adjacent to the lateral border of an area of acute myocardial ischemia.