Incidence, Relevant Patient Factors, and Clinical Outcomes of the Misdiagnosis of ST‐Segment–Elevation Myocardial Infarction: Results From the Korea Acute Myocardial Infarction Registry

Background Data on the incidence, relevant patient factors, and clinical outcomes of the misdiagnosis of ST‐segment–elevation myocardial infarction (STEMI) in the modern era of percutaneous coronary intervention are limited. Methods and Results Data from KAMIR (Korea Acute Myocardial Infarction Registry) between November 2011 and June 2020 were analyzed. Out of 28 470 patients with acute myocardial infarction, 11 796 were eventually diagnosed with STEMI following a coronary angiogram. They were classified into 2 groups: patients with an initial working diagnosis of STEMI before starting the initial treatment and patients with an initial working diagnosis of non‐STEMI (misdiagnosed group). Out of 11 796 patients with a final diagnosis of STEMI, 165 (1.4%) were misdiagnosed. The door‐to‐angiography time in the misdiagnosed group was 5 times longer than that in the timely diagnosed group (median 220 [interquartile range {IQR}, 66–1177] versus 43 [IQR, 31–58] minutes; P