[Anisoinotropism of myocardial cells: elementary histological picture of early ischemic dys-asynergy].

Twelve autoptic hearts from victims of cardiogenic shock, within a few hours from infarction, were studied at light microscope. At the site of early ischemia, a discrepancy in contraction of myocardiocytic units along single fibers (otherwise normal) has been observed. It configurated as an asynergic contracture (with Z lines impinging upon A bands), side by side with relaxed elements (with evident I bands); frequent dehiscence of intercalated disks ensues, due to imbalanced mechanic strain. These morphologic features, only rarely seen in 20 control hearts, are consistent with pertinent knowledge in pathophysiology, and can be defined "anisoinotropism" of myocardial fibers. They seem to be the microscopic substrate for the contractile dys-asynergy, which is credited in modern clinical diagnostics among the earliest signs of cardiac ischemia. The discal injury may also imply an impairment in intercellular conductivity, with an arrhythmogenic potential (reentry). Anisoinotropism presents as the forerunner of the well known "contraction band degeneration-necrosis", by progressive coagulative denaturation of the contractile proteins, up to conglutination and cancellation of sarcomere structures. The changes described herein can be taken into consideration in histopathology of heart's acute ischemia, before the occurrence of patent pictures of initial infarction.