The "athletic heart". Prevalence and physiological significance of left ventricular enlargement in distance runners

Abstract

To evaluate the prevalence and importance of physiological left ventricular hypertrophy (LVH) in athletes, 30 marathon runners were studied. ECG evidence of LVH, present in 24 subjects, was associated with concomitant echocardiographic evidence of a thickened left ventricular (LV) posterior wall in 5, with an enlarged end-diastolic LV diameter in 3, and with roentgenographic evidence of cardiomegaly in 3 subjects. Echocardiographic evidence of superior LV function was noted in 6. Maximal treadmill stress provoked no ischemic change. Cardiac hypertrophy and dilatation commonly develop in well-conditioned athletes, but the changes in LV size are slight. This physiological type of LVH does not lead to an ischemic response during exercise, in contrast to that which is seen in pathological forms of LVH. Physiological LVH may, however, contribute to superior ventricular function.