The relative distribution of coronary blood flow in rats with moderate and marked left ventricular hypertrophy

Publisher Website
Google Scholar
Abstract
A reduced capillary density associated with hypertrophy evoked by pressure overload may impose limitations on coronary flow. To determine the effect of moderate and marked left ventricular hypertrophy on regional myocardial blood flow at rest we studied 53 anesthetized, open-chest rats with radioactive 7- to 10-μm microspheres. Spontaneously hypertensive (SHR) and aortic-constricted rats with left ventricular weight to body weight ratios 38 and 92% greater, respectively, than their normotensive controls provided a contrast between two distinct magnitudes of hypertrophy. Blood flow ratios (left ventricular subendocardium to subepicardium and left to right septum) were used as indices of relative distribution of myocardial blood flow.The data show that mean blood flow ratios were similar in hypertrophic and nonhypertrophic hearts despite the limitations of subnormal perfusion pressures inherent in the experimental conditions. Similarly total left ventricular flow per unit mass was not altered by either magnitude of hypertrophy. Thus, it is concluded that circulatory adjustments and cardiac reserve in the hypertrophic myocardium are sufficient to maintain normal distribution of coronary flow under resting conditions, even when cardiac mass increases nearly twofold.