Structural and functional heterogeneity of cardiomyocytes during hemodynamic overloading of the rat heart

: Ultrastructural studies of cardiomyocytes during experimental aorta coarctation enabled one to divide them into 6 types: with mitochondrial swelling and enlargement of the sarcoplasmic reticulum; with primary damage to myofibrils; with disintegration of ultrastructure because of edema; with hypertrophy and hyperplasia of ultrastructures; without essential changes in organelles; and with concomitant changes in mitochondria and myofibrils. Such different reactions of cardiomyocytes are regarded as an adaptation mechanism that ensures the maintenance of heart function under extreme conditions.