Indexing left ventricular mass to account for differences in body size in children and adolescents without cardiovascular disease.

Left ventricular (LV) mass has been established as an independent risk factor for cardiovascular disease morbidity and mortality. To account for differences in body size, a variety of factors have been proposed for indexing LV mass. Dual energy x-ray absorptiometry provides a measure of lean body mass which can be used as a comparison with other more clinically applicable methods of standardization. The study included 192 subjects (100 male, 103 white) aged 6 to 17 years. Lean body mass was determined by dual energy x-ray absorptiometry and LV mass was calculated from M-mode echocardiographic measurements. There were significant differences by gender (males 98.7 g, females 80.3g, p < 0.001), but not race, for unindexed LV mass. Indexing LV mass by lean body mass eliminated the difference by gender. Log-log regression analysis revealed that the optimal height exponent for indexing LV mass was height3 (95% confidence interval, 2.8 to 3.1). LV mass/height3 provided the most consistently high intraclass correlation with LV mass/lean body mass versus indexing with body surface area, height, height2, and height2.7 across the 4 race/gender groups. LV mass indexed by height3 eliminated differences in LV mass by gender (males 26.1 +/- 4.72 g/m3, females 25.5 +/- 4.8 g/m3, p = NS). The proposed method for indexing LV mass by height3 should be useful in the clinical setting. The 90th and 95th percentiles of LV mass/height3 provide cutpoints for determining the presence of LV hypertrophy in children and adolescents.