EFFECT OF GROWTH ON VARIABILITY OF LEFT-VENTRICULAR MASS - ASSESSMENTOF ALLOMETRIC SIGNALS IN ADULTS AND CHILDREN AND THEIR CAPACITY TO PREDICT CARDIOVASCULAR RISK

Objectives. We sought to determine whether growth influences the relat ion between left ventricular mass and body size and whether use of dif ferent body size indexes affects the ability of ventricular mass to pr edict complications of hypertension. Background. Allometric (or growth ) signals between left ventricular mass and height have recently been reported to improve previous approaches for normalization of ventricul ar mass for body size. Methods. Residuals of left ventricular mass-hei ght(2.7) relations were analyzed in a learning series of 611 normotens ive, normal weight subjects 4 months to 70 years old and, separately, in 383 children (<17 years old) and 228 adults. Ten year cardiovascula r morbidity in a test series of 253 hypertensive adults was compared w ith groups with normal or high baseline left ventricular mass normaliz ed for body weight, height, body surface area and allometric powers of height. Results. The dispersion of residuals of ventricular mass vers us height(2.7) increased with increasing height or age in children but not in adults, suggesting that the effect of other variables on ventr icular growth increases during body growth and stabilizes in adulthood . Therefore, we derived separate allometric signals for adults (predic ted ventricular mass = 45.4 x height(2.13), r = 0.48) and children (32 .3 x height(2.3), r = 0.85) (both p < 0.0001), Patients with left vent ricular hypertrophy had 3.3 times higher cardiac risk with elevated le ft ventricular mass/height(2.7) (p < 0.001), 2.6 to 2.7 times higher r isk with left ventricular mass indexed for height, height(2.13) and bo dy surface area (all p < 0.01) and 1.7 times the risk with ventricular mass/weight (p > 0.1). Conclusions. These results show the following: 1) Variability of left ventricular mass in relation to height increas es during human growth; 2) allometric signals of left ventricular mass versus height are lower in adults and children than those obtained ac ross the entire age spectrum; 3) height-based indexes of left ventricu lar mass at least maintain and may enhance prediction of cardiac risk by hypertensive left ventricular hypertrophy; and 4) the allometric si gnal derived across the entire spectrum of age appears to be more usef ul for prediction of cardiovascular risk than that computed in adults.