Biopsy evidence of atrial myocarditis in an athlete developing transient sinoatrial disease.

Atrial myocarditis causing transient sinoatrial disease (incessant atrial tachycardia alternating with sinoatrial pauses of up to 6 s in duration) in an athlete is reported. Diagnosis was undertaken by endomyocardial biopsy; biventricular and right atrial specimens were obtained. After a 6-month rest period, the atrial arrhythmias disappeared, and the athlete was able to resume his professional sporting activities.