[Morphological study of the myocardium in children and adults under normal conditions and in hypoxia].

At the light and electronic microscopes, 32 myocardial biopsies from 16 patients were studied. The study was carried out in 8 children under 5 years of age and in 8 adults over 20 years during open-sky surgery of the chest done to correct some congenital or acquired heart anomaly. Control biopsies were taken before the application of extracorporeal circulation and a second biopsy, after an average of 30 minutes of hypoxia, which was the time taken to perform the surgical correction of the anomaly.