Abstract
Diagnosis of ST-segment changes is challenging in patients with right ventricular pacing rhythm. Herein, we present a patient with a history of permanent His-bundle pacemaker implantation who developed chest pain and ST-segment changes on electrocardiography. An immediate diagnosis of acute myocardial infarction on the basis of the electrocardiographic abnormality and prompt management of coronary intervention resulted in a short door-to-balloon time of 80 minutes, even on a holiday morning, and a stable clinical course thereafter. This scenario underscores the potential benefit of electrocardiographic diagnosis in physiological pacing using a native conduction system, associating prompt treatment with a favorable prognosis.