The athlete's heart syndrome: a new perspective.

Although earlier electrocardiographic and roentgenographic studies suggested that the heart of trained athletes differed from that of nonathletes, little was known of the cardiac dimensions of the athlete's heart until the advent of echocardiography. Echocardiographic studies have demonstrated that trained athletes may have increased left ventricular mass and that the structural change accounting for this increase is related to the type of physical conditioning. Athletes participating primarily in isotonic exercise have an increase in left ventricular end-diastolic volume with little or no increase in left ventricular wall thickness whereas those athletes participating primarily in isometric exercise have an increase in left ventricular wall thickness associated with normal left ventricular end-diastolic volume. Comparisons between echocardiographically determined cardiac changes in college and world class athletes were made, and the electrocardiographic and chest roentgenographic changes present in the athlete's heart syndrome were reviewed.