Reconstruction of the microscopic transmural edge of experimentally infarcted canine myocardium.

Experimental myocardial infarction of the posterolateral left ventricular wall in 2 dog hearts, the result of 1 h of occlusion of the left circumflex coronary artery followed by 4 days of reperfusion, was studied post mortem by serial histological sectioning. Microscopic examination in a transverse plane showed a zone of apparent necrotic muscle removal which formed a continuous boundary between necrotic and normal myocardium without outlying, detached "islands" of necrosis. Reconstruction of the histological transmural edge of infarction at its interface with viable subepicardial muscle demonstrated wide overlapping and angulated interdigitation of the separated tissues across the midzone of the ventricular wall. The observed 3-dimensional spatial complexity of the transmural infarct boundary may be a limiting factor in successful evaluation of this experimentally important region.