title: 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.
abstract: OBJECTIVE
  Identification 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.
  
  
  METHODS
  Each 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.
  
  
  RESULTS
  Thirty 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.
  
  
  CONCLUSIONS
  ED 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.
authors.affiliation: Accident and Emergency Department, Changi General Hospital, Singapore, Singapore.
authors.forename: Hoon Chin Steven
authors.initials: HC
authors.lastname: Lim
authors.affiliation: Accident and Emergency Department, Changi General Hospital, Singapore, Singapore.
authors.forename: Edgar Azada
authors.initials: EA
authors.lastname: Salandanan
authors.affiliation: Biostatistics Department, Singapore Clinical Research Institute, Singapore, Singapore.
authors.forename: Rachel
authors.initials: R
authors.lastname: Phillips
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
authors.forename: Jun Guan
authors.initials: JG
authors.lastname: Tan
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
authors.forename: Muhammad Azmi
authors.initials: MA
authors.lastname: Hezan
mesh_terms: D000328:Adult; D053840:Brugada Syndrome; D000075224:Cardiac Conduction System Disease; D004562:Electrocardiography / Q000379:methods*; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies
keywords: ECG, interpretation; cardiac care, acute myocardal infarct; cardiac care, diagnosis