Background: The physiological determinants of left ventricular mass (LVM) measured by cardiac magnetic resonance (CMR) imaging are not well defined as prior investigators have studied either adults or adolescents in isolation or have not strictly excluded hypertension or accounted for the effects of exercise habits, haemodynamic, demographic, or body shape characteristics.
Methods: Ninety-seven healthy volunteers (11-81 years, 51 males) underwent CMR. All parameters [unstandardized and adjusted for body surface area (BSA)] were analysed according to gender and by adolescence versus adulthood (adolescents<20 years, adults>or=20 years). The influence of haemodynamic factors, exercise and demographic factors on LVM were determined with multivariate linear regression.
Results: Left ventricular mass rose during adolescence and declined in adulthood. LVM and LVMBSA were higher in males both in adults (LVM: 188+/-22 versus 140+/-21 g, P<0.001; LVMBSA: 94+/-11 versus 80+/-11 g m(-2), P<0.001) and in adolescents when adjusted for BSA (LVM: 128+/-29 versus 107+/-20 g, P=0.063; LVMBSA: 82+/-8 versus 71+/-10 g m(-2), P=0.025). In adults, systolic blood pressure (SBP) and self-reported physical activity increased while meridional and circumferential wall stress were constant with age. Multivariate regression analysis revealed age, gender and BSA as the major determinants of LVM (global R2=0.68).
Conclusions: Normal LVM shows variation over a broad age range in both genders with a rise in adolescence and subsequent decline with increasing age in adulthood despite an increase in SBP and physical activity. BSA, age and gender were found to be major contributors to the variation in LVM in healthy adults, while haemodynamic factors, exercise and wall stress were not.