A 50-year-old man with a dual-chamber pacemaker was admitted to our hospital complaining of chest pain. Anterior ST segment elevation myocardial infarction (STEMI) was diagnosed. Emergency coronary angiography revealed total occlusion of the proximal left anterior descending artery (LAD), and primary percutaneous coronary intervention was performed. Angiograms showed that the LAD was wrapped around the apex of both ventricles. On day 8, ventricular fibrillation and cardiopulmonary arrest occurred due to elevation of the pacing threshold because of pacemaker malfunction. The pacemaker was upgraded to an implantable cardioverter-defibrillator and the lead was inserted into the right ventricular septum. Myocardial scintigraphy with thallium-201 and technetium-99m pyrophosphate located the infarct zone around the apex of both ventricles. We conclude that pacing failure of the right ventricular lead occurred in this case of LAD occlusion due to a LAD supplying the right ventricular apex. Clinicians should be aware of the possibility of pacemaker failure in patients presenting with anterior STEMI due to a wrap-around LAD. <Learning objective: Pacemaker failure due to right ventricular lead malfunction can also occur in patients presenting with myocardial infarction of the left coronary arteries. In our case the culprit lesion was located in the left anterior descending artery, which wrapped around the apex to supply parts of the right ventricle.>.
Keywords: Myocardial infarction; Myocardial scintigraphy; Pacemaker malfunction; Wrap-around left anterior descending artery.