Relationship between cardiac parameters and cube root of BSA corrected by subcutaneous fat weight

Left ventricular internal dimension (LVIDd), aortic root dimension (AOD) and left atrial dimension (LAD) were measured echocardiographically in 688 normal children, ranging in age from 5 to 15. Lean body surface area (BSA) was calculated from height and lean body weight which was estimated from triceps skin fold thickness, upper arm circumference and body weight. Cardiac parameters (LVIDd, AOD, LAD) were well correlated with 3 square root BSA or 3 square root lean BSA (r = 0.72 approximately 0.89). Regression lines of LVIDd and AOD against 3 square root BSA or 3 square root lean BSA were compared between boys and girls. Statistically significant sex difference was observed in regression lines of LVIDd and AOD plotted against BSA (p less than 0.005), but this difference disappeared when plotted against lean BSA. It is concluded that the sex difference of LVIDd and AOD corresponding to a similar BSA depended on the difference of lean body weight between boys and girls.