Left ventricular adaptation to hypertension and plasma renin activity

Abstract

Chronic pressure and volume overload result in morphologically and functionally distinct forms of myocardial hypertrophy. In essential hypertension, the respective effect of these factors on the morphology of the left ventricle remains unknown. In the present study, we hypothesised that activity of the renin angiotensin system (assessed by plasma renin activity) may be associated to the variability of the left ventricular adaptation to essential hypertension. To assess this relation, we categorised by echocardiography 333 never-treated hypertensive patients, according to values of left ventricular mass and relative wall thickness. Higher systolic and pulse arterial pressure was strongly associated with concentric left ventricular hypertrophy (27% of hypertensives). When compared to the normal left ventricle group, patients with eccentric left ventricular hypertrophy (15% of hypertensives) had a high cardiac index (5 ± 1 vs 4 ± 0.8 L/min/m²; P = 0.0001), a lower basal plasma renin activity (0.81 ± 0.63 vs 1.45 ± 1.3 ng/ml/h; P = 0.02) and similar mean values of left ventricular performance and glomerular filtration rate. A tendency for depressed myocardial contractility assessed by the midwall shortening/end-systolic stress was associated with concentric left ventricular remodelling and hypertrophy when compared to hypertensive with a normal left ventricle. In conclusion, at the early phase of essential hypertension, in patients without renal dysfunction, each anatomic pattern of cardiac adaptation to hypertension was associated with a distinct profile of haemodynamics, myocardial function and activity of the renin-angiotensin system.