Structural heart adaptations in triathletes

Objective - To perform a triathlon in aerobic conditions, a variety of card iovascular, haemodynamic and metabolic adaptations are required. The heart is the central concern and also the most important limiting factor. In this study we investigate the structural and functional heart adaptations of a group of triathletes. Methods and results - A group of 52 male triathletes was divided into 4 sub groups in function of their athletic results and com pared with a control g roup of 22 healthy, very active but no athletic men. The groups had compara ble anthropometric and general physical characteristics. Very significant differences in cardiac structure and cardiac function we r e observed between the groups. In the triathletes, we registered distinct s igns of significantly mixed eccentric and concentric hypertrophy. Unlike th e findings in a pathological left ventricular hypertrophy, the diastolic le ft ventricular function in triathletes was completely normal and even bette r than in the control group. The late passive diastolic filling period of t he triathlete, in particular, seemed to have specific characteristics. The comparison between the subgroups of triathletes shows us that genetic facto rs probably play an important role in the cardiac adaptations in triathlete s. Conclusions - In our opinion the "athletic heart" in triathletes is not a s pecific "physiological entity" but is a transitional phase to a dilated hyp ertrophic cardiomyopathy. Our study yields some arguments for the following proposition: "People are born as elite athletes, with specific characteristics of the left ventricle and with a specifically supernormal diastolic left ventricular function."