[Disorders of myocardial contractile capacity in patients with an interatrial septal defect complicated by bacterial...

After performing 242 operations on patients with secondary atrial septal defects under conditions of moderate hypothermia, the authors studied the contractile capacity of the myocardium by means of long-term catheterization of the heart chambers in 56 patients. In 35 patients of this group intravital biopsy of the right ventricle was carried out. The bioptic material was subject to light and electron microscopy and histochemical examination. Considerable changes in intracardiac hemodynamics were revealed in patients with bacterial endocarditis. In such cases the diastole changes most sharply: the phase of isometric relaxation was prolonged, and there was a sharp rise in the maximum rate of intraventricular pressure decrease and in the relaxation index, which indicated to disorders of metabolic processes in the myocardium, conducive to the manifestation of myocardial insufficiency.