title: Agreement in electrocardiogram interpretation in patients with septic shock.
abstract: OBJECTIVE
  The reliability of electrocardiogram interpretation to diagnose myocardial ischemia in critically ill patients is unclear. In adults with septic shock, we assessed intra- and inter-rater agreement of electrocardiogram interpretation, and the effect of knowledge of troponin values on these interpretations.
  
  
  METHODS
  Prospective substudy of a randomized trial of vasopressin vs. norepinephrine in septic shock.
  
  
  METHODS
  Nine Canadian intensive care units.
  
  
  METHODS
  Adults with septic shock requiring at least 5 μg/min of norepinephrine for 6 hrs.
  
  
  METHODS
  Twelve-lead electrocardiograms were recorded before study drug, and 6 hrs, 2 days, and 4 days after study drug initiation.
  
  
  METHODS
  Two physician readers, blinded to patient data and group, independently interpreted electrocardiograms on three occasions (first two readings were blinded to patient data; third reading was unblinded to troponin). To calibrate and refine definitions, both readers initially reviewed 25 trial electrocardiograms representing normal to abnormal. Cohen's Kappa and the φ statistic were used to analyze intra- and inter-rater agreement.
  
  
  RESULTS
  One hundred twenty-one patients (62.2 ± 16.5 yrs, Acute Physiology and Chronic Health Evaluation II 28.6 ± 7.7) had 373 electrocardiograms. Blinded to troponin, readers 1 and 2 interpreted 46.4% and 30.0% of electrocardiograms as normal, and 15.3% and 12.3% as ischemic, respectively. Intrarater agreement was moderate for overall ischemia (κ 0.54 and 0.58), moderate/good for "normal" (κ 0.69 and 0.55), fair to good for specific signs of ischemia (ST elevation, T inversion, and Q waves, reader 1 κ 0.40 to 0.69; reader 2 κ 0.56 to 0.70); and good/very good for atrial arrhythmias (κ 0.84 and 0.79) and bundle branch block (κ 0.88 and 0.79). Inter-rater agreement was fair for ischemia (κ 0.29), moderate for ST elevation (κ 0.48), T inversion (κ 0.52), and Q waves (κ 0.44), good for bundle branch block (κ 0.78), and very good for atrial arrhythmias (κ 0.83). Inter-rater agreement for ischemia improved from fair to moderate (κ 0.52, p = .028) when unblinded to troponin.
  
  
  CONCLUSIONS
  In patients with septic shock, inter-rater agreement of electrocardiogram interpretation for myocardial ischemia was fair, and improved with troponin knowledge.
authors.affiliation: Department of Medicine, Interdepartmental Division of Critical Care Medicine, Mount Sinai Hospital, USA.
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Mehta
authors.forename: John
authors.initials: J
authors.lastname: Granton
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Lapinsky
authors.forename: Gary
authors.initials: G
authors.lastname: Newton
authors.forename: Kristofer
authors.initials: K
authors.lastname: Bandayrel
authors.forename: Anjuli
authors.initials: A
authors.lastname: Little
authors.forename: Chuin
authors.initials: C
authors.lastname: Siau
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Cook
authors.forename: Dieter
authors.initials: D
authors.lastname: Ayers
authors.forename: Joel
authors.initials: J
authors.lastname: Singer
authors.forename: Terry C
authors.initials: TC
authors.lastname: Lee
authors.forename: Keith R
authors.initials: KR
authors.lastname: Walley
authors.forename: Michelle
authors.initials: M
authors.lastname: Storms
authors.forename: Jamie
authors.initials: J
authors.lastname: Cooper
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Holmes
authors.forename: Paul
authors.initials: P
authors.lastname: Hebert
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Gordon
authors.forename: Jeff
authors.initials: J
authors.lastname: Presneill
authors.forename: James A
authors.initials: JA
authors.lastname: Russell
mesh_terms: D015415:Biomarkers / Q000097:blood; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000503:physiopathology; D009638:Norepinephrine / Q000627:therapeutic use; D015588:Observer Variation; D011446:Prospective Studies; D012772:Shock, Septic / Q000188:drug therapy / Q000503:physiopathology*; D013997:Time Factors; D014336:Troponin / Q000097:blood; D014662:Vasoconstrictor Agents / Q000627:therapeutic use; D014667:Vasopressins / Q000627:therapeutic use
chemical_list: D015415:Biomarkers; D014336:Troponin; D014662:Vasoconstrictor Agents; D014667:Vasopressins; D009638:Norepinephrine