title: ECG signs of acute myocardial ischemia in the prehospital setting of a suspected acute coronary syndrome and its association with outcomes.
abstract: OBJECTIVE
  The aims of this study were (a) to determine the prehospital prevalence of electrocardiographic (ECG) signs of acute myocardial ischemia in patients with suspected acute coronary syndrome and (b) to describe the relationships between the various ECG patterns and the diagnosis of acute myocardial infarction (AMI) and outcomes.
  
  
  METHODS
  Prospective cohort study using data from an interventional trial in acute chest pain patients transported by the emergency medical services. These patients were classified into 3 groups: patients with ECG showing signs of acute myocardial ischemia, patients with ECG showing other abnormal changes (bundle-branch block, pacemaker rhythm, Q-wave or T-wave inversion) and patients without significant pathologic findings. All P values are age-adjusted.
  
  
  RESULTS
  Among 1546 patients, 312 (20%) had ECG signs of acute myocardial ischemia. Of them, 57% had a final diagnosis of AMI versus 26% of those with other abnormal ECGs and 12% of those with ECG without significant pathologic findings (P<.0001). In all, 53% of all AMI cases involved patients without ECG signs of acute myocardial ischemia. Although ECG signs of acute myocardial ischemia predicted heart failure and ventricular tachyarrhythmias both prior to and after hospital admission, there was no significant difference in 30-day mortality between the 3 patient groups (4.3%, 3.7%, and 1.2%, respectively, P=.11).
  
  
  CONCLUSIONS
  Among patients with a clinical suspicion of AMI in the prehospital setting, the prevalence of ECG signs suggesting AMI was low, as was the ability to identify AMI patients using ECG findings only. We therefore need better instruments in the prehospital triage of patients with acute chest pain.
authors.affiliation: Department of Molecular and Clinical Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden. Electronic address: victordangthang@hmu.edu.vn.
authors.forename: Nguyen Dang
authors.initials: ND
authors.lastname: Thang
authors.affiliation: School of Health Sciences, Research Centre PreHospen, University of Borås, The Prehospital Research Centre of Western Sweden, Sweden.
authors.forename: Birgitta Wireklint
authors.initials: BW
authors.lastname: Sundström
authors.affiliation: Centre for Applied Biostatistics, Occupational and Environmental Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Karlsson
authors.affiliation: Department of Molecular and Clinical Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden; School of Health Sciences, Research Centre PreHospen, University of Borås, The Prehospital Research Centre of Western Sweden, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Herlitz
authors.affiliation: Department of Molecular and Clinical Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden; AstraZeneca R&D, Mölndal, Sweden.
authors.forename: Björn Wilgot
authors.initials: BW
authors.lastname: Karlson
mesh_terms: D054058:Acute Coronary Syndrome / Q000175:diagnosis / Q000503:physiopathology*; D000368:Aged; D002637:Chest Pain / Q000175:diagnosis / Q000503:physiopathology; D004562:Electrocardiography; D004632:Emergency Medical Services / Q000706:statistics & numerical data; D005260:Female; D006321:Heart / Q000503:physiopathology; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000175:diagnosis / Q000503:physiopathology; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000503:physiopathology*; D011446:Prospective Studies