Relationships of cardiac and somatic growth in infancy and childhood.

Recent advances at clinical and experimental levels bespeak the need for a more complete understanding of cardiac growth and its relationship to somatic growth. The size of the heart is integral to several physiologic processes, including aerobic and work capacity, athletic performance, and reproduction. Because the morphologic foundations for cardiac size are laid in large part before adulthood, cardiac growth and the factors controlling it are important in achieving optimal cardiovascular fitness. We provide a baseline for normal cardiac growth during the late fetal to adolescent periods. Sexual differences are not evident in this prepubertal population. Heart weight is related to three measures of body and chest size. These relationships follow a hierarchy, whereby heart weight is most closely related to body weight, followed by body length, then chest circumference. The association of heart weight with chest circumference is a secondary one, reflecting more primary relationships between heart weight and body weight and length. Deviations from this normal hierarchy occur in certain environments and disease states.