Paroxysmal atrioventricular block: A case report

Paroxysmal atrioventricular block (PAVB) is an abrupt shift from normal conduction to complete heart block. Because episodes are transient and ECGs may appear normal between events, the condition is frequently overlooked. A 73-year-old male presented with recurrent near-syncope and intermittent bradycardia. In the ED, a premature atrial complex triggered sudden complete heart block without preceding PR or sinus slowing, consistent with intrinsic PAVB. He required transcutaneous and then transvenous pacing, and ultimately received a leadless ventricular pacemaker. Coronary angiography showed chronic disease unlikely to explain his conduction abnormality, and he remained asymptomatic at one year. PAVB is life-threatening and easily missed without continuous monitoring. Early identification and prompt pacing are critical to prevent prolonged asystole and sudden cardiac death.