A case of spontaneous pneumothorax presenting with high-degree atrioventricular block.

The myocardial electrical conduction is significantly influenced by the sympathetic and parasympathetic nervous systems. Hypervagotonia refers to increased vagal tone leading to sinus bradycardia, sinus pause, or any degree of atrioventricular (AV) block. There are many clinical, electrocardiographic, and electrophysiologic clues that help make the diagnosis of hypervagotonia as the cause of bradyarrhythmias. We describe a case of spontaneous pneumothorax presenting with symptomatic high-degree AV block and subsequent electrophysiologic diagnosis of hypervagotonia. The patient had complete resolution of his bradycardia and AV block after chest tube placement. This case is intended to alert cardiologists to this rare presentation of spontaneous pneumothorax.