title: Improving the ECG classification of inferior and lateral myocardial infarction by inversion of lead aVR.
abstract: OBJECTIVE
  To assess whether the use of inverted lead aVR (-aVR) would improve the classification of acute inferior or lateral myocardial infarction presenting with ST elevation.
  
  
  METHODS
  Observational study. The presence of >/= 1 mm ST elevation in lead -aVR (derived by manual assessment of ST depression in conventional lead aVR) was determined by a single investigator, blinded to patient outcome.
  
  
  METHODS
  173 consecutive patients with chest pain for </= 12 hours and ST elevation of >/= 1 mm in inferior leads (II, III, aVF) or lateral leads (I, aVL, V5, V6), excluding those with anterolateral ST elevation.
  
  
  METHODS
  Incidence of ST elevation in lead -aVR in patients with inferior or lateral ST elevation, or both.
  
  
  RESULTS
  ST elevation in lead -aVR was present in 25 of 136 patients (18%) with inferior but no lateral ST elevation (indicating greater superior involvement) and in three of 11 patients (27%) with lateral but no inferior ST elevation (indicating greater inferior involvement). ST elevation in lead -aVR bridged the gap between inferior and lateral ST elevation in 15 of 25 (60%) patients with inferior and lateral chest lead (V5/V6) ST elevation, and in all patients with inferior and lateral limb lead (I/aVL) ST elevation. The presence of ST elevation in lead -aVR was associated with a larger infarct size as defined by median peak creatine kinase on serial sampling: 1780 v 987 mmol/l; p = 0.021.
  
  
  CONCLUSIONS
  Use of lead -aVR improves the ECG classification of acute inferior or lateral acute myocardial infarction and thus may be useful as part of the routine 12 lead ECG assessment of such patients.
authors.affiliation: Regional Medical Cardiology Centre, Royal Victoria Hospital, Grosvenor Road, Belfast BT12 6BA, Northern Ireland, UK.
authors.forename: I B
authors.initials: IB
authors.lastname: Menown
authors.forename: A A
authors.initials: AA
authors.lastname: Adgey
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D015331:Cohort Studies; D003402:Creatine Kinase / Q000097:blood; D004562:Electrocardiography / Q000379:methods*; D004566:Electrodes; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012044:Regression Analysis
chemical_list: D015415:Biomarkers; D003402:Creatine Kinase