Heritability of cardiac size: an echocardiographic and electrocardiographic study of monozygotic and dizygotic twins.

Abstract

Because of the uncertainty as to the extent to which cardiac size is determined by exercise training vs genetic endowment, this study investigated familial (genetic plus common family environment) vs nonfamilial influences on cardiac size. College-age monozygotic twins (group 1, 31 sets), dizygotic twins (group 2, 10 sets), siblings of like sex (group 3, six sets), and nonrelated subjects (group 4, 15 sets) underwent echocardiographic and electrocardiographic tests, measurement of maximum oxygen uptake (VO2max), and evaluation of pulmonary and body composition; mean intrapair differences of the four groups were compared. Mean intrapair differences in cardiac size varied as much for subjects in group 1 as for those in groups 2 and 3. However, subjects in groups 1, 2, and 3 had less variation (p < .

Maternal and Paternal Influences on Left Ventricular Mass of Offspring

“…In the present analysis we did not examine the cross-trait intrafamilial relations between left ventricular mass and anthropometric characteristics. However, in keeping with the high heritability of anthropometric characteristics in twin studies, 34 we found sib-sib correlation coefficients of 0.52 for height and 0.30 for weight. We also noticed a significant concordance of height between spouses, which is likely to be due to by assortive mating.…”

Left ventricular mass and exercise responses predict future blood pressure. The Muscatine Study.

“…28 These data implicate a genetic predisposition in some with a strong family history of essential hypertension that may facilitate the development of cardiovascular changes at pressure loads that are borderline-elevated or of relatively short duration. Perhaps increased LVM in part is a phenotypic expression rather than a result of high blood pressure.…”

Sibling correlation of left ventricular mass and geometry in hypertensive African Americans and whites: the HyperGEN study

“…4 -8 Genetic influences on factors regulating myocardial growth or hemodynamics may be responsible for the etiology of increased mass, although information regarding the overall genetic influence on LV mass is limited. 4,8 The heritability (h 2 ) of heart size (P Ͻ .002) in baboons is 0.39 and, in humans, falls between 0.22 and 0.59. 4,5,8 The LV remodels in response to physiologic stimuli (eg, increased peripheral vascular resistance, arterial stiffening, and plasma volume expansion), creating a variety of LV geometric phenotypes in hypertensive subjects.…”