Reversible heart block following nonpenetrating chest trauma.

Blunt chest trauma, if sustained selectively to the midchest or precordium, can result in a variety of cardiac injuries (3, 7). These lesions may involve separately or together all structures of the heart, including pericardium, myocardium, valves, and coronary arteries. Depending on the extent of trauma, such injuries can cause varying amounts of mechanical or electrical dysfunction. The incidence and nature of cardiac dysrhythmias following trauma are largely unknown clinically, but have been extensively documented in several animal studies (2, 4, 5). Disturbances in both impulse generation and transmission were noted, usually beginning immediately after impact with the development of complete heart block and progressing quickly through several other electrical patterns to either sinus rhythm or ventricular fibrillation. High-grade atrioventricular (A-V) block has rarely been recognized clinically in association with nonpenetrating heart trauma (1), perhaps because of its rapid replacement by other dysrhythmias. It was, therefore, of interest when a patient presented to this institution in third-degree heart block following a blunt chest injury. Specifics of her illness are discussed.