THE ECG OF THE ATHLETES HEART

The athlete's heart is characterized by eccentric hypertrophy of all c ardiac cavities and there is a close connection to increased tone of t he vagal system. As a consequence, not only arrhythmias are observed i n the ECG of healthy athletes, but also changes in the QRS complex and in the ST-T-segment. Left ventricular hypertrophy is diagnosed in ECG by a positive Sokolow-Lyon index. The frequent finding of a right ven tricular conduction delay is possibly due to hypertrophy of the myocar dium in the apex of the right ventricle. The causes of various T wave changes are generally unclear and await further diagnostic clarificati on. In cases when normalization of the T-wave deviation is observed un der stress, such changes are of functional nature. Echocardiography is indicated in any case to establish the heart's size and function; hyp ertrophic cardiomyopathy has to be excluded. Frequent cardiac dysrhyth mias found in athletes are sinus bradycardia and sinus arrhythmia, les s often escape rhythms are seen. A arrhythmia more often found in athl etes is the respiration-dependent simple atrioventricular dissociation . Also, escape rhythms are observed in some cases with ventricular ori gin. Finally, a pronounced vagotonia can lead to a prolonged conductio n time; AV-blocks of all degrees of severity are observed in athletes. The functional character of these arrhythmias can be easily demonstra ted by their disappearance under stress.