Use of polarized-light microscopy in histological diagnostics of early stages of ischaemic and metabolic myocardial lesions.

Animal experiments have proved that the earliest morphological manifestations of acute lesions of myocardial cells (at the optical microscopic level) are myofibrillar changes detectable by polarized-light microscopy. As basic types of myocardial cell lesions there can be distinguished segmental and subsegmental contractures, intracellular myocytolysis, and primary granular disintegration. These changes persist in animal myocardium for many hours and thus can be recognized at autopsy. The application of polarized-light microscopy makes possible a diagnosis of early stages of myocardial infarction, associated with lesions of myocardial cells appearing at the periphery of the ischaemic zone already within the first minutes, revelation of focal metabolic changes leading to acute heart failure, and diagnosis of ventricular fibrillation, characterized by subsegmental contractures of the subepicardial and subendocardial layers of the myocardium.