The coronary circulation in hypertensive heart disease

This study analyzes and compares systemic and coronary hemodynamics in patients with essential hypertension in relation to hypertrophic heart disease of nonhypertensive origin. Left ventricular function (as assessed from the cardiac index, stroke volume index, ejection fraction, mean velocity of circumferential fiber shortening, mean normalized systolic ejection rate, and isovolumic indexes) may be normal in patients with hypertensive hypertrophy, even with a large increase in muscle mass and in the presence of concomitant coronary artery disease. Left ventricular function is impaired when regional contraction abnormalities or ventricular dilatation, or both, occur and is inversely related to both cardiac size and systolic wall stress. Coronary blood flow (+ 18%), coronary resistance (+ 38%), and myocardial oxygen consumption (MVO2) (+ 21%) are increased in essential hypertension. Coronary reserve is reduced even in hypertensive hypertrophy without evidence of coronary artery disease. MVO2 per mass unit was directly correlated with systolic wall stress per cross-sectional area of the left ventricular wall. Coronary reserve may remain normal in both moderate and excessive hypertrophy, provided systolic wall stress and hence the myocardial oxygen consumption are not increased. It is concluded that the appropriateness of left ventricular hypertrophy, as a result of mass-to-volume ratio and stress, is a major determinant of left ventricular performance, of coronary blood flow, and of myocardial oxygen consumption.