title: Value of posterior and right ventricular leads in comparison to the standard 12-lead electrocardiogram in evaluation of ST-segment elevation in suspected acute myocardial infarction.
abstract: In this multicenter prospective trial, we studied posterior (V7 to V9) and right ventricular (V4R to V6R) leads to assess their accuracy compared with standard 12-lead electrocardiograms (ECGs) for the diagnosis of acute myocardial infarction (AMI). Patients aged >34 years with suspected AMI received posterior and right ventricular leads immediately after the initial 12-lead ECG. ST elevation of 0.1 mV in 2 leads was blindly determined and inter-rater reliability estimated. AMI was diagnosed by World Health Organization criteria. The diagnostic value of nonstandard leads was determined when 12-lead ST elevation was absent and present and multivariate stepwise regression analysis was also performed. Of 533 study patients, 64.7% (345 of 533) had AMI and 24.8% received thrombolytic therapy. Posterior and right ventricular leads increased sensitivity for AMI by 8.4% (p = 0.03) but decreased specificity by 7.0% (p = 0.06). The likelihood ratios of a positive test for 12, 12 + posterior, and 12 + right ventricular ECGs were 6.4, 5.6, and 4.5, respectively. Increased AMI rates (positive predictive values) were found when ST elevation was present on 6 nonstandard leads (69.1%), on 12 leads only (88.4%), and on both 6 and 12 leads (96.8%; p <0.001). Treatment rates with thrombolytic therapy increased in parallel with this electrocardiographic gradient. Logistic regression analysis showed that 4 leads were independently predictive of AMI (p <0.001): leads I, II, V3, V5R; V9 approached statistical significance (p = 0.055). The standard ECG is not optimal for detecting ST-segment elevation in AMI, but its accuracy is only modestly improved by the addition of posterior and right ventricular leads.
authors.affiliation: Department of Emergency Medicine, Cook County Hospital, and Center for Health Services Research, School of Public Health, University of Illinois at Chicago 60612, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Zalenski
authors.forename: R J
authors.initials: RJ
authors.lastname: Rydman
authors.forename: E P
authors.initials: EP
authors.lastname: Sloan
authors.forename: K H
authors.initials: KH
authors.lastname: Hahn
authors.forename: D
authors.initials: D
authors.lastname: Cooke
authors.forename: J
authors.initials: J
authors.lastname: Fagan
authors.forename: D J
authors.initials: DJ
authors.lastname: Fligner
authors.forename: W
authors.initials: W
authors.lastname: Hessions
authors.forename: D
authors.initials: D
authors.lastname: Justis
authors.forename: L M
authors.initials: LM
authors.lastname: Kampe
authors.forename: S
authors.initials: S
authors.lastname: Shah
authors.forename: J
authors.initials: J
authors.lastname: Tucker
authors.forename: D
authors.initials: D
authors.lastname: Zwicke
mesh_terms: D000368:Aged; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results