A 56-year-old man presented with right coronary arterial spasm accompanied by ST segment elevation in the inferior leads. A reperfusion arrhythmia, accelerated idioventricular rhythm (AIVR), developed 1 hour after a nitroglycerin infusion. The AIVR was sustained for 5 days without hemodynamic instability, and resolved spontaneously during hemodynamic monitoring in the coronary intensive care unit.