title: Right precordial and posterior electrocardiographic leads do not increase detection of ischemia in low-risk patients presenting with chest pain.
abstract: BACKGROUND
  A number of innovative approaches have been investigated for their value in the early detection of acute ischemia or infarction in patients presenting to the emergency department (ED) with chest pain suggestive of a cardiac origin. Prior investigations have demonstrated the utility of adding right precordial and posterior chest leads to the standard 12-lead electrocardiogram (ECG) for identifying right ventricular and posterior wall infarctions in the ED.
  
  
  OBJECTIVE
  To assess the utility of additional ECG leads in low-risk patients presenting to the ED with symptoms suggestive of acute coronary syndromes who are managed in a chest pain evaluation unit (CPEU).
  
  
  METHODS
  We studied low-risk patients who presented to the ED with chest pain compatible with myocardial ischemia. Low-risk patients were identified by a normal 12-lead ECG, no arrhythmias or hemodynamic instability, and one negative serum cardiac troponin I. Patients were admitted to the CPEU where a 16-lead ECG was recorded by the addition of 2 right-sided precordial leads (V4R, V5R) and 2 posterior leads (V8, V9) to the standard 12-lead ECG.
  
  
  RESULTS
  The 16-lead ECG system was applied to 316 consecutive patients. The study group was a middle-aged population with equal numbers of men and women and an average of 2 cardiac risk factors per patient. The 16-lead ECG demonstrated evidence of myocardial injury in only 1 patient and no evidence of ischemia in any of the 316 patients.
  
  
  CONCLUSIONS
  In patients presenting to the ED with chest pain and evidence of low clinical risk by our criteria, the addition of both right-sided precordial and posterior chest leads to the standard 12-lead ECG did not provide additional information for risk stratification.
authors.affiliation: Divisions of Cardiovascular Medicine and Emergency Medicine, Department of Internal Medicine, University of California School of Medicine (Davis) and Medical Center (Sacramento), Sacramento, Calif 95817, USA.
authors.forename: Rick P
authors.initials: RP
authors.lastname: Ganim
authors.forename: William R
authors.initials: WR
authors.lastname: Lewis
authors.forename: Deborah B
authors.initials: DB
authors.lastname: Diercks
authors.forename: Douglas
authors.initials: D
authors.lastname: Kirk
authors.forename: Rajendran
authors.initials: R
authors.lastname: Sabapathy
authors.forename: Larry
authors.initials: L
authors.lastname: Baker
authors.forename: Ezra A
authors.initials: EA
authors.lastname: Amsterdam
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000175:diagnosis; D002637:Chest Pain / Q000209:etiology*; D004562:Electrocardiography / Q000379:methods*; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis; D017202:Myocardial Ischemia / Q000150:complications / Q000175:diagnosis*