Syncope and 2:1 Atrioventricular Block in a Middle-Aged Man

A man in his early 50s with no cardiovascular risk factors presented after a brief syncopal episode and was found to have bradycardia with 2:1 atrioventricular block on electrocardiogram. Careful inspection of the inferior leads showed hyperacute T waves with subtle ST-segment elevation and reciprocal ST-segment depression, suggesting evolving inferior occlusion myocardial infarction. He underwent urgent coronary angiography, which revealed proximal right coronary artery occlusion, followed by successful percutaneous revascularization. This case highlights that syncope with new atrioventricular block may reflect acute coronary occlusion requiring early reperfusion therapy.

Syncope with newly developed bradyarrhythmia or atrioventricular block warrants meticulous assessment of the inferior leads for subtle ischemic changes, even when chest pain is absent. Dynamic hyperacute T waves with reciprocal inferior ST-segment changes in high-grade atrioventricular block should prompt suspicion of early inferior occlusion myocardial infarction; reperfusion is the key treatment for this symptomatic bradycardia.