Usefulness of the phenomenon of histofluorescence in the identification of early myocardial necrosis.

To evaluate the histological phenomenon of fluorescence of necrotic myocardium in ultraviolet light a prospective study of fatal myocardial infarction with accurate clinical and biochemical correlation was made. To test the morphological characteristics and specificity of the technique experimental infarctions were induced surgically in sheep and pigs and acute ischaemia and infarction induced by catheter in intact dogs. Fluorescence was visible within five minutes of the injury in routinely stained sections and persisted for as long as cellular debris was identifiable. It was independent of autolysis, optimal fixation, prolonged storage, and special stains. Although the fluorescence was associated with hypereosinophilia in stained sections, necrotic myocardium also fluoresced in unstained ones, demonstrating primary or autofluorescence. Fluorescence microscopy is a useful adjunct to the histological identification of early myocardial necrosis and of scattered or focal necrosis especially in the absence of myocardial infarction.