[Stereologic analysis of myocardial ultrastructure during the postresuscitation period].

The myocardium of dogs which suffered the 5-minute clinical death was subjected to ultrastructural stereologic examination. It was found that the T system density volume in cardiac myocytes was drastically reduced because of the massive destruction of its tubules. The regeneration of the T system was slow in progress. The mitochondrial density volume was discovered to be reduced 6 hours after the resuscitation. The myocardial ultrastructure virtually returned to normal by the end of the second week of the postresuscitation period.