The influence of body composition on left ventricular mass and other echocardiographic and Doppler measurements in 70-year-old males

Abstract

Heart morphology and function are often related to body size. The most common way to standardize for body composition is to divide these measures by body surface area (BSA). It has, however, been suggested that left ventricular mass (LV mass) ought to be indexed for height and that cardiac output is influenced by the body fat distribution. As part of a health screening programme of 70-year-old males in Uppsala, Sweden, 100 consecutive men were investigated with echocardiography and Doppler with regard to cardiac morphology and function. These measures were related to an evaluation of body composition using an X-ray method (dual energy X-ray absorptiometry). Lean body mass was strongly related to BSA and body weight (r = 0.90 and 0.89, respectively; P < 0.0001), and to a lesser degree to height (r = 0.70, P < 0.0001). In the healthy part of the population (n = 39), relationships between LV mass on the one hand and lean body mass, BSA and height on the other were seen (r = 0.51, 0.51 and 0.50, respectively; P < 0.01). Stroke volume calculated according to Teichholtz (but not when calculated with Doppler) showed a significant correlation to lean body mass (r = 0.38, P < 0.05). Also, left ventricular diameter and the thickness of the free wall were related to lean body mass (r = 0.40 and 0.39, respectively; P < 0.05). All of the evaluated relationships were generally weaker and in most cases no longer significant when evaluated in part of the population with diseases known to affect the heart. No significant correlations were seen between the size of the left atrium, septal thickness or indices of diastolic function (E/A-ratio, isovolumic relaxation time, deceleration time) and the indices of body composition. No measures of cardiac morphology and function were significantly related to the amount of body fat or body bone. LV mass, stroke volume and left ventricular diameter were found to be correlated with lean body mass, but not with the amount of fat, in healthy 70-year-old males. Theoretically, it is optimal to adjust for lean body mass, but in clinical practice, BSA is to be preferred.