A novel method of expressing left ventricular mass relative to body size in children.

BACKGROUND Left ventricular (LV) hypertrophy (LVH) in children is widely defined as a left ventricular mass index (LVMI, g/m(2.7)) >95th percentile. However, LVMI increases with decreasing height in young children; thus, the 95th percentile LVMI will depend on the height distribution of the reference population. The objective of this study was to compare the performance of a novel method of expressing LV mass relative to body size (centile curves) with the LVMI method. METHODS AND RESULTS LV mass was estimated by M-mode echocardiography in 440 healthy nonobese reference children (birth to 21 years) and 239 children at risk for LVH; the LVMI was calculated for all children. Three samples of 270 children, each with different height distributions, were drawn from the reference population. A sample-specific 95th percentile LVMI was determined for each reference sample. At-risk children were classified as having LVH or not based on each sample-specific 95th percentile. Four LV mass-for-height centile curves were constructed with the Cole lambda-mu-sigma method and data from each reference sample. At-risk children were each assigned an LV mass-for-height percentile with these curves and were reclassified as having LVH if LV mass-for-height was >95th percentile. The centile method provided a stable estimate of the proportion of at-risk children with LVH regardless of reference group, whereas proportion estimates varied significantly depending on the reference population when the LVMI method was used. CONCLUSIONS LV mass-for-height centile curves are superior to LVMI as a method of normalizing LV mass to body size in children.