EKG's                           Multi-lead EKG's
                                ----------------

þ 22-lead
  22-lead EKGs are better than 12-lead at diagnosing MI.  A prospective study
  of 163 patients, 41 with an MT by enzymes, showed:
                12-lead 22-lead
  Sensitivity:  51%     83%
  Specificity:  76%     99%
  [Justis DL, Hession WT.  Accuracy of 22-lead ECG analysis for diagnosis of
  acute myocardial infarction and coronary artery disease in the emergency
  department: a comparison with 12-lead ECG.  Ann Emerg Med 1992; 21(1):1-9.]

þ 15-lead
 - adding leads V4R, V8, V9 made EKGs more specific (59% vs. 47%) with the
   same specificity (93%)
   [Zelenski RJ, et al.  Assessing the diagnostic value of an ECG containing
   leads V4R, V8 and V9:  the 15-lead ECG.  Ann Emerg Med 1993;22(5):786.]

þ Interpreting Multilead EKGs
 - can sum the ST elevation over multiple leads to improve diagnostic accuracy
 - even 1 mm ST elevation may be significant in rightsided or posterior leads
   [Brian A. Nester, DO, MS, FACOEP, 1998 PaACEP conference]