Isolated posterior ST-elevation myocardial infarction: the necessity of routine 15-lead electrocardiography: a case series

Background: True isolated posterior myocardial infarction is an uncommon finding of acute coronary syndrome, with an incidence rate of 3–7%. The prevalence rates of isolated posterior myocardial infarction in men and women are 72% and 28%, respectively. This uncommon finding may be attributed to multiple factors, such as unremarkable changes on 12-lead electrocardiography, a lack of awareness or knowledge, and an absence of diagnostic consensus, which leads to reperfusion delay and poor clinical outcomes. Case summary: Herein, we report three cases of acute myocardial infarction presenting as isolated ST-segment elevation in the posterior leads (V7–V9): Asian men aged 57, 62, and 53 years, who presented with ST-segment depression in V1–V3 that resolved gradually. Coronary angiography revealed a total/critical occlusion of the proximal circumflex coronary artery in all three cases. Routine and accurate interpretations of 15-lead electrocardiography (12-lead with additional V7–V9) resulted in a better sensitivity for isolated posterior myocardial infarction diagnoses, followed by a timely and opportune primary percutaneous coronary intervention. Conclusions: Isolated posterior myocardial infarction is a rare but potentially fatal event that is often accompanied by atypical and subtle changes on 12-lead electrocardiography (especially in the V1–V3 precordial leads) and may remain undetected by physicians. Therefore, the comprehensive and routine application of posterior leads is a crucial addition to the standard diagnosis and management of acute coronary syndrome in patients with subtle ST-segment changes who do not fulfill the criteria for ST-elevation myocardial infarction.