[Change in the mitochondria of the left heart ventricle in the intact rabbit during the course of the day (based on scanning electron microscopic data)].

The myocardium of the left ventricle of intact rabbit was investigated by scanning electron microscopy during 24 hours, namely at 0, 6 a.m., noon and 6 p.m. It was discovered that the mitochondria reach the maximal volume at 6 p.m. and the minimal at 6 a.m. The qualitative differences in the mitochondria at different periods of the day are described. A correlation was established between the swelling of the mitochondria and some indices of heart function.