Echocardiographic assessment of cardiac chamber size and left ventricular function in aerobically trained athletes

We compared the echocardiographic assessment of left ventricular function in 20 aerobically trained male athletes (VO2 max 61 ml/kg/min) with 20 control subjects of similar age and size (VO2 max 37 ml/kg/min). On average, the left ventricle was larger in athletes and the extent of myocardial contraction (fractional shortening) was reduced. In nine athletes, fractional shortening was less than our laboratory lower limit of normal (26%) and in four athletes the left ventricle was enlarged and fractional shortening was reduced. However, the peak rate of circumferential shortening was not reduced in athletes. We concluded that athletes have normal myocardial contractility but some have a reduced extent of myocardial contraction which could be mistaken for the effects of myocardial disease.