Sinoatrial Wenckebach associated with blunt cardiac injury.

A 20-year-old man developed sinoatrial Wenckebach after moderate blunt chest and cardiac trauma from a motor vehicle accident. This unusual dysrhythmia is manifested by grouped beating, a constant PR interval, progressive shortening of the cycle length, and repetitive pauses. Sinoatrial Wenckebach has not previously been described in association with blunt cardiac injury.