Inter-rater reliability of J-point location and measurement of the magnitude of ST segment elevation at the J-point on ECGs of STEMI patients by emergency department doctors

• Published in: Emergency medicine journal : EMJ Vol. 32; no. 10; pp. 809 - 812
• Main Authors: Lim, Hoon Chin Steven, Salandanan, Edgar Azada, Phillips, Rachel, Tan, Jun Guan, Hezan, Muhammad Azmi
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 01.10.2015
• Subjects: Adult; Agreements; Brugada Syndrome; Cardiac Conduction System Disease; Electrocardiography; Electrocardiography - methods; Emergency medical care; Emergency Service, Hospital - statistics & numerical data; Female; Heart attacks; Humans; Male; Middle Aged; Myocardial Infarction - diagnosis; Observer Variation; Reproducibility of Results; Retrospective Studies; Studies; cardiac care, acute myocardal infarct; ECG, interpretation; cardiac care, diagnosis
• DOI: 10.1136/emermed-2014-204102
• ISSN: 1472-0205

Introduction and objectivesIdentification of the J-point and measurement of ST segment elevation at the J-point are important for the diagnosis of ST-elevation myocardial infarction (STEMI). We conducted a study to determine the inter-rater reliability (IRR) of J-point location and measurement of the magnitude of ST elevation at the J-point on ECGs of patients with STEMI by emergency department (ED) doctors.Subjects and methodsEach participant examined 20 STEMI ECGs during a 1-month period in 2013. The participants were required to locate the J-point by selecting the small 1 mm square within which the J-point is located and measure the magnitude of ST elevation at the J-point identified (rounded up to the nearest 0.5 mm). The intraclass correlation coefficient (ICC) was calculated to assess the IRR.ResultsThirty doctors participated. The ICC assessing the degree to which all participants provided agreement in their assessment of the location of J-points across ECGs was 0.85 (95% CI 0.75 to 0.93), which is in the excellent range. The ICC for assessing the magnitude of ST elevation was 0.97 (95% CI 0.94 to 0.98), indicating excellent agreement as well.ConclusionsED doctors show a high level of agreement when determining the location of J-points and measuring the magnitude of ST elevation at those J-points on ECGs of patients with STEMI. The findings support the measurement of ST segment elevation at the J-point in STEMI cases and should be regarded as a consistent standard to avoid confusion.