The electrocardiographic findings in more than 20, 000 athletes are studied.
I. Resting electrocardiograms (ECG) of 10, 149 high school athletes are analysed. Abnormal ECG are encountered in 12.45%. Following findings are found: Right bundle branch block (RBBB) (4.03%), Left ventricular hypertrophy (2.89%), Premature beats (1.09%), A-V block (0.86%), Right ventricular hypertrophy (0.85%) . RBBB are further analysed and divided into 4 types from the QRS pattern in V1. The frequent RBBB in young athletes is confirmed and its significance is also discussed.
II. T wave abnormalities are observed in 5 cases of resting ECGs of all this sample. Essential abnormalities are T wave inversion simulating myocardial infarction in limbs leads (usually in II, III, aVF) and precordial leads and concomitant slight elevation in precordial leads.
Physical and laboratory examinations in 5 cases disclose no evidence of organic heart disease. In 4 of 5 cases, exercise ECGs are revealed the normalisation-tendency of the T wave change. A brief discussion concerning the possible mechanisms of these changes are made.
III. ECGs of middle and old age athletes are also observed at rest and after the long distance running. The distance are different in each age-group, but all of them run at least more than 5 km. The 409 resting ECGs are taken before the running game and the 201 post running tracing are obtained as soon as possible after the game.
At rest, ECG findings suggestive of coronary insufficiency are detected in 4 of 108 samples of sixties group and in 1 of 25 samples of seventies group.
Ischemic electrocardiographic responses after the running game are found as follow: 3/51 (5.8%) of fourties group, 9/59 (15.1%) of fifties group, 20/70 (28.6%) of sixties group and 6/21 (28.6%) of over seventies group.
Arrhythmias are not so frequently observed in each group. These ischemic re-sponses suggest that medical check-up especially cardiovascular evaluation is necessary in middle and old age athletes to prevent accidents on sports.