2018 Volume 82 Issue 7 Pages 1836-1843
Background:Cardiac size measurements require indexing to body size. Allometric indexing has been investigated in Caucasian populations but a range of different values for the so-called allometric power exponent (b) have been proposed, with uncertainty as to whether allometry offers clinical utility above body surface area (BSA)-based indexing. We derived optimal values forbin normal echocardiograms and validated them externally in cardiac patients.
Methods and Results:Values forbwere derived in healthy adult Chinese males (n=1,541), with optimalbfor left ventricular mass (LVM) of 1.66 (95% confidence interval 1.41–1.92). LV hypertrophy (LVH) defined as indexed LVM >75 g/m1.66was associated with adverse outcomes in an external validation cohort (n=738) of patients with acute coronary syndrome (odds ratio for reinfarction: 2.4 (1.1–5.4)). In contrast, LVH defined by BSA-based indexing or allometry using exponent 2.7 exhibited no significant association with outcomes (P=NS for both). Cardiac longitudinal function also varied with body size: septal and RV free wall s’, TAPSE and lateral e’ all scaled allometrically (b=0.3–0.9).
Conclusions:An optimalbof 1.66 for LVM in healthy Chinese was found to validate well, with superior clinical utility both to that of BSA-based indexing and tob=2.7. The effect of allometric indexing of cardiac function requires further study.
