[Effect of experimental myocardial hypertrophy on coronary microcirculation in the rat].

Effects of cardiac hypertrophy on coronary capillary density and volume have been studied in two models: systemic hypertension (1c. 2K Goldblatt model, n = 27), and volume overload (aorto-caval fistula, n = 27) compared to a control group (n = 27). Studies have been performed at 1 month, 3 and 6 months. Subendocardial and subepicardial coronary capillaries have been visualized by in injection of fluorescein-labeled dextran (FITC). The body weights were not significantly different in the three groups. The heart weight was the same in hypertensive model and fistula. Goldblatt model was associated with a high blood pressure and an increase in left ventricular wall thickness, whereas fistula was associated with a lower blood pressure and no difference in wall thickness as compared to controls. No difference in subepicardial capillary density was found in the three groups, whereas the subendocardial capillary density was decreased in the two models of cardiac hypertrophy (-25%). Capillary area and mean perimeter, were increased in fistula, due to vasodilatation, and decreased in Goldblatt model in relation to vasoconstriction.