Echocardiographic evaluation of long-term effects of exercise on left ventricular hypertrophy and function in professional bicyclists.

Echocardiographic examinations were performed in 60 professional bicyclists and control subjects to determine the effects of exercise on left ventricular hypertrophy and function. The athletes were separated by age into three groups: group 1 (n = 14), 20-29 years; group 2 (n = 17), 30-39 years; and group 3 (n = 29), 40-49 years. Echocardiograms showed enlargment of the left ventricular end-diastolic dimensions in all three groups compared with age-matched control groups (p less than 0.001). Thickness of the interventricular septum and the left ventricular posterior wall was more prominent in group 3 of the athletes than groups 1 and 2 of the athletes and control group (p less than 0.001). Resting left ventricular function evaluated with fractional shortening, ejection fraction and mean velocity of circumferential fiber shortening was significantly depressed in group 3 compared with the other groups. Moreover, 14% of group 3 subjects showed enlargement of left atrial dimension and T-wave inversion in the left precordial leads of the ECG. We conclude that left ventricular hypertrophy is an important ventricular adaptation in relatively young athletes. However, middle-aged athletes may be more susceptible to electrocardiographic abnormalities and prominent hypertrophy, and some may have slightly depressed left ventricular function.