Abstract 9689: Left Ventricular Mass Normalized to Lean Body Mass in Children May Obscure the Effect of Hypertension on the Heart
Purpose: In order to make comparisons of left ventricular mass (LVM) measurements among children, several methods of LVM normalization for body size have been developed. LVM has been hypothesized to correlate best with lean body mass (LBM). In addition, hypertension is a known risk factor for left ventricular hypertrophy. This study evaluates the agreement between LVM normalized to LBM (LVML) and LVM normalized to body surface area (LVMB) or height (LVMH). In addition the study evaluates the relationship between each method and systemic blood pressure. Our hypothesis is that LVM normalization to LBM will obscure the effect of hypertension on the LVM.
Methods: Echocardiograms performed from 2009-2010 in 206 children (118 males, age 4 to 18 years) with no structural heart disease or systemic disorders other than hypertension and obesity were analyzed. LVM was calculated from M mode images using the prolate ellipsoid formula. LVM Z scores were calculated using 3 different published nomograms adjusting for height, BSA, and LBM. Intraclass correlation coefficients (ICC) with absolute agreement of single measures were used to assess concordance between LVML Z score with the LVMB and LVMH Z scores. Pearson correlation was done to assess the associations.
Results: Among the 206 patients, 21% had hypertension, 38% were obese, and 10% were obese and hypertensive. Mean BMI Z score was 1.1 ± 1.2, systolic BP Z score 0.6 ± 1.2, and diastolic BP Z score 0.1 ± 0.9. The ICC between LVML and LVMB Z scores was 0.81 (95th% CI: 0.73-0.86, p < 0.001) and between LVML and LVMH Z scores was 0.73 (95th% CI: 0.29-0.87, p < 0.001). Correlations of the 3 LVM Z scores with BP, weight, and BMI Z scores are shown in the table.
Conclusion: LVML has a better correlation with LVMB compared to LVMH. Elevated systolic BP associate with higher LVMH. There was no significant relationship between systolic BP and LVML or LVMB, suggesting that these methods of LVM normalization may mask the effect of hypertension on LVM.
- © 2013 by American Heart Association, Inc.