Relation of left ventricular hemodynamic load and contractile performance to left ventricular mass in hypertension

A Ganau, R B Devereux, T G Pickering, M J Roman, P L Schnall, S Santucci, M C Spitzer, J H Laragh
1990 Circulation  
The weak relation of systolic blood pressure to left ventricular mass in hypertensive patients is often interpreted as evidence of nonhemodynamic stimuli to muscle growth. To test the hypothesis that left ventricular chamber size, reflecting hemodynamic volume load and myocardial contractility, influences the development of left ventricular hypertrophy in hypertension, we studied actual and theoretic relations of left ventricular mass to left ventricular diastolic chamber volume, pressure and
more » ... ume, pressure and volume load, and an index of contractility. Data were obtained from independently measured M-mode and two-dimensional echocardiograms in 50 normal subjects and 50 untreated patients with essential hypertension. Two indices of overall left ventricular load were assessed: total load (systolic blood pressureX left ventricular endocardial surface area) and peak meridional force (systolic blood pressure x left ventricular cross sectional area). A theoretically optimal left ventricular mass, allowing each subject to achieve mean normal peak stress, was calculated as a function of systolic blood pressure and M-mode left ventricular end-diastolic diameter. Left ventricular mass measured by M-mode echo correlated better with two-dimensional echocardiogram derived left ventricular enddiastolic volume (r=0.56, p<0.001) than with systolic blood pressure (r=0.45, p<0.001) and best with total load or peak meridional force (r=0.68 and 0.70, p<0.001). In multivariate analysis both end-diastolic volume and blood pressure were independent predictors of systolic mass (p <0.001) and explained most of its variability (R=0.75,p <0.001). Theoretically optimal left ventricular mass was more closely related to end-diastolic volume (r= 0.72, p<0.001) than to systolic blood pressure (r=0.46,p<0.001); thus, the relatively weak correlation between blood pressure and optimal mass reflected the influence of left ventricular cavity size, rather than a lack of proportionality between load and hypertrophy. Actual and theoretically optimal left ventricular mass were closely related (r=0.76, p<0.001), indicating that left ventricular hypertrophy in most cases paralleled hemodynamic load. Left ventricular mass was positively related to stroke index and inversely to contractility (as estimated by the end-systolic stress/volume index ratio), the main determinants of left ventricular chamber volume. In multivariate analysis, systolic blood pressure, stroke index, and the end-systolic stress/volume index ratio were each independently related to left ventricular mass index (all p<0.001, multiple R=0.81) and accounted for 66% of its overall variability. These observations suggest that left ventricular chamber size, reflecting hemodynamic profile and inotropic properties, is a major determinant of the degree of left ventricular hypertrophy in hypertension. Theoretic left ventricular mass describes ideal relations among blood pressure, cavity size, and mass, providing evidence that a weak relation between systolic blood pressure and left ventricular mass is compatible with adequate left ventricular load-mass coupling. Total load and peak meridional force, incorporating both pressure and left ventricular geometry, are better predictors of left ventricular mass than systolic blood pressure. (Circulation 1990;
doi:10.1161/01.cir.81.1.25 pmid:2297829 fatcat:wwslmujlpje5hlbvxdflfaj3ee