title: Availability of a baseline Electrocardiogram changes the application of the Sclarovsky-Birnbaum Myocardial Ischemia Grade.
abstract: OBJECTIVE
  The electrocardiogram (ECG) based Sclarovsky-Birnbaum Ischemia Grade may be used to determine the prognosis of patients with ST-elevation myocardial infarction (STEMI). However, application of the method is based on assumption of the baseline QRS morphology. Thus, the aims of this study were to determine if the baseline QRS morphology was correctly assumed based on an ECG recorded during induced ischemia, and if reference to the baseline ECG altered the designated Ischemia Grade.
  
  
  METHODS
  Sixty-three patients with chronic ischemic heart disease that underwent elective percutaneous transluminal coronary angioplasty were included. Baseline ECG and ECG during the procedure were recorded. In the latter, Ischemia Grade was classified according to assumed baseline QRS morphology. Then the baseline ECG was used as reference and Ischemia Grade was determined based on change from the baseline ECG.
  
  
  RESULTS
  In 66.6% (42/63) of patients the criteria for STEMI were fulfilled; the incidence was similar between left anterior descending (LAD) and right coronary artery (RCA) occlusion. In LAD patients who fulfilled STEMI criteria, assumption of baseline QRS morphology in involved leads was accurate in only 35% (7/20) and this altered the Ischemia Grade in 10% (2/20) of patients. In RCA patients who fulfilled STEMI criteria, assumption of baseline QRS morphology in involved leads was accurate in 77.3% (17/22) and this altered the Ischemia Grade in 9.1% (2/22) of patients.
  
  
  CONCLUSIONS
  Application of the Sclarovsky-Birnbaum Ischemia Grade with reference to a baseline ECG altered Ischemia Grade in approximately 10% of patients. All patients that were reclassified were assigned a higher Ischemia Grade. Future research is needed to determine the impact of availability of the baseline ECG on the clinical diagnostic and prognostic performances of the Sclarovsky-Birnbaum Ischemia Grade.
authors.affiliation: Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark. Electronic address: e_a_carlsen@hotmail.com.
authors.forename: Esben A
authors.initials: EA
authors.lastname: Carlsen
authors.affiliation: Department of Cardiology, The Heart Center, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Lia E
authors.initials: LE
authors.lastname: Bang
authors.affiliation: Department of Cardiology, The Heart Center, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Lars
authors.initials: L
authors.lastname: Køber
authors.affiliation: Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food & Drug Administration, Silver Spring, MD, USA.
authors.forename: David G
authors.initials: DG
authors.lastname: Strauss
authors.affiliation: Division of Cardiology, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: Matias
authors.initials: M
authors.lastname: Amaral
authors.affiliation: Division of Cardiology, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Barbagelata
authors.affiliation: Chesapeake Cardiac Care, Annapolis, MD, USA.
authors.forename: Stafford
authors.initials: S
authors.lastname: Warren
authors.affiliation: Duke University Medical Center, Durham, NC, USA.
authors.forename: Galen S
authors.initials: GS
authors.lastname: Wagner
mesh_terms: D000465:Algorithms; D003936:Diagnosis, Computer-Assisted / Q000379:methods* / Q000592:standards; D004562:Electrocardiography / Q000379:methods* / Q000592:standards*; D006801:Humans; D038622:Internationality; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis*; D012016:Reference Values; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
keywords: Electrocardiogram; Myocardial ischemia; STEMI; Sclarovsky-Birnbaum Ischemia Grade