Cardiac arrhythmias are the reason of the most sudden deaths in athletes. The 
annual risk of sudden death at athletes is between 5 to 10 per one million. 
Benign arrhythmia including bradyarrhythmias, atrial and ventricular premature 
contractions are common in the athletes. Supraventricular arrhythmias such as 
atrial fibrillation, nodal reciprocal entrant tachycardia and 
Wolff-Parkinson-White syndrome are less common. Perhaps the rarest and the most 
dangerous arrhythmias are ventricular arrhythmias, among them arrhythmias 
secondary to hypertrophic cardiomyopathy, arrhythmogenic right ventricular 
dysplasia, long QT syndrome, and anomalous origin of coronary arteries. 
Asymptomatic bradyarrhythmias (if the heart rate in bradyarrhythmia appropriate 
increases with exercise), supraventricularis tachycardias, and atrial premature 
contractions without structural heart disease are not the contraindication to 
sports Athletes with premature ventricular contraction, nonsustained ventricular 
tachycardia and non structural heart disease are without athletic restrictions 
as long as the arrhythmias do not worsen and they not cause dyspnea or 
presyncope during exertion. Frequent or multiform premature ventricular 
contraction or sustained ventricular tachycardia indicate a higher risk, and all 
participation in athletic should be restricted.