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. 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.