Electrocardiographic and echocardiographic characteristics of long distance runners. Comparison of left ventricular function with age- and sex-matched controls.

Nineteen long distance runners and 19 age- and sex-matched sedentary controls were evaluated by echocardiography and electrocardiography (ECG) at rest and after 12 minutes of treadmill exercise. Seven of ten male athletes exhibited ECG abnormalities of prominent precordial voltage, early repolarization, and one had right ventricle hypertrophy; only three of nine females had ECG abnormalities. The resting and postexercise heart rates and blood pressures were lower in athletes than controls (P less than 0.001). The athletes increased their left ventricular end-diastolic volume and stroke volume and had a moderate increase in heart rate. Controls markedly increased only their heart rate to the same level of exercise. One female athlete and one female control had 1 mm of ST segment depression with exercise. The right ventricular wall thickness was equal to or greater than 6 mm in athletes versus equal to or less than 5 mm in controls. The left ventricular wall was thicker in athletes than controls, the resultant left ventricular mass was 60% more in athletes due to left ventricular hypertrophy (P less than 0.001). We concluded left ventricular hypertrophy is present in athletes as a result of endurance running.