[Morphological study of the myocardium in children and adults under normal conditions and in hypoxia]. / Estudio morfológico de miocardio de niños y adultos en condiciones normales y en la hipoxia

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. Following extracorporeal circulation, all cases showed mitochondrial mutuations, such as disorganization of their crests, marked distension, from edema to emptiness due to hypoxia. The lack of glycogen, the disorganization of the myofibrillae, decreased neatness of the sarcoplasm and nuclei with marginated chromation, were all preceded by mitochondrial mutations due to oxidative phosphorylation deficiency.