This distinction has significant clinical implications, the
researchers said. While enlargement of the heart can be a
natural and beneficial response to exercise training, it can
also be an early warning sign for such harmful conditions as
heart failure. These findings, based on a series of experiments
in mice, could help settle a long-running controversy among
cardiologists concerning heart enlargement, or cardiac
hypertrophy, according to Duke cardiologist Howard Rockman,
M.D., who led the team of Duke and University of North Carolina-
Chapel Hill researchers. The researchers published their
findings on June, 1, 2006, in the Journal of Clinical
Investigation. The study was supported by the National
Institutes of Health. "If you look at the hearts of athletes,
they are larger than normal," Rockman said. "On the other hand,
patients with high blood pressure also tend have larger-than-
normal hearts. So why are some cardiac overloads, such as
exercise, good for the heart, while others, such as high blood
pressur