Morphophysiopathologic studies on the biology of myocardium in acquired valvulopathies

Myocardial lesions due to various valvulopathies were sampled during open heart surgery under extracorporeal circulation, and histologically, histoenzymologically and ultrastructurally investigated. Various cardiomyocitary and interstitial nonspecific progressive lesions, due especially to hemodynamic and hypoxic alterations, were identified. During the pathogenic stages, we remarked the onset and chronic evolution of perivascular and interstitial oedema, enhanced by a reduced lymph draining. The progressive processes of hyalinization, sclerosis and interstitial fibrosis were subsequent to the interstitial matrix modification. These processes accentuate the myocardial hypoxic lesion due to the nutritional and gaseous exchange alterations. The infrastructure, mitochondrial enzyme equipment, sarcoplasma and tubular network lesions, as well as the intramyocitary oedema that destroys the sarcomeric structure, ended with the activation of lysosome and lysosomal enzymes, giving rise to consequent cytolytic foci. Therefore, the process was extending. In this context, we remarked at the electronmicroscopic examination ventricular natriuremic granules, that are rarely mentioned in literature.