[Condition of the sarcolemma of subendocardial Purkinje cells in the late stages of experimental myocardial infarction in the dog].

The ultrastructure of subendocardial Purkinje fibers of the dogs left heart ventricle was studied 24 hours after ligation of the descending left coronary artery. The structure of the collagen layer and glycocalyx of the sarcolemma were studied by staining with ruthenium red and the structure of the plasmalemma by staining with colloidal lanthanum. Electron microscopy shows that in the ischemic zone, the Purkinje fibers lose their external collagen layer of sarcolemma. A part of the Purkinje fibers were contracted, glycocalix of their sarcolemma was thinner and more translucent as compared to the control. The plasma membrane remained nonpenetrable for colloidal lanthanum. It is suggested that the changes in the external part of the sarcolemma observed may be responsible for the increased sensitivity of the Purkinje fibers of the ischemic zone to antiarrhythmic drugs.