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Common STEMI Imitators: Part 2 There are other causes of ST-segment elevation besides myocardial infarction A s we discussed last month, besides improving our ability to identify STEMIs in the feld, the addition of the 12-lead ECG in the prehospital environment can also lead us to inadvertently misidentify a number of etiologies of ST-segment elevation that don't result from ACS and STEMI. A STEMI imitator (Table 1) can place a patient at increased risk if they are administered unneces- sary medications (nitroglycerin, aspirin, morphine or fbrinolytics), and the unnecessary activation of STEMI teams and catheterization labs leads to wasted resources. The November article covered benign early repolarization (BER), acute pericarditis, Brugada syndrome and left bundle branch block (LBBB). This month's article continues a case-based approach to explore some additional STEMI imitators. Case #1: Ventricular Paced Rhythm An obese 60-year-old male presents conscious, alert and oriented to person, place, time and event, sitting on a couch, complaining of chest discomfort. He describes an acute onset of discomfort about an hour ago after eating dinner. The discomfort is described as retrosternal, nonreproducible, burning, nonradi- ating, and a 6 on a scale of 0–10. It is slightly relieved with belching. He says he's been experiencing the discomfort "about every day or two" for the past three weeks, and tonight the pain is worse. He also describes frequent episodes of dysphagia and regurgitation that started about three weeks ago. The patient denies any difficulty breathing, nausea, vomiting, weakness, dizziness, syncope, and abdominal or back pain. His past medical history includes two AMIs, with a ventricular pacemaker implant three years ago; hypertension; type 2 diabetes; a sliding hiatal hernia diagnosed three months ago; and a 46-pack-a- year smoking history. His medications include aspirin, Plavix, diltiazem and glimepiride, and he has no known drug allergies. Your clinical exam reveals nothing remarkable. He has no JVD or peripheral edema, and his lungs are clear and equal bilaterally. There is no trauma to his chest, and no pain with palpation of his chest wall or sternum. His pacemaker implant site appears normal. His blood glucose is 112 mg/dL; other vitals are HR, 72/min.; BP, 128/72 mmHg; RR, 12/min. with good tidal volume; SpO 2 , 97% on room air; temperature, 98.1ºF (36.7ºC) tympanic. Per your protocol you perform a 12-lead ECG, shown in Figure 1. What is your interpretation of this This CE activity is approved by EMS World, an organization accredited by the Continuing Education Coordinating Board for Emergency Medical Services (CECBEMS), for 1 CEU. OBJECTIVES • List the common cardiac rhythms that are STEMI imitators • Describe the 12-lead ECG characteristics of paced cardiac rhythm, increased intracranial pressure and left ventricular hypertrophy • Given a 12-lead ECG, identify each of the following cardiac rhythms: paced cardiac rhythm, increased intracranial pressure and left ventricular hypertrophy • Differentiate between STEMI and each of the following STEMI imitators: paced cardiac rhythm, increased intracranial pressure and left ventricular hypertrophy CONTINUING EDUCATION To take the CE test that accompanies this article and receive 1 hour of CE credit accredited by CECBEMS, go online to www.rapidce.com. Test costs $6.95. Questions? E-mail editor@EMSWorld.com. | By Scott R. Snyder, BS, NREMT-P, Sean M. Kivlehan, MD, MPH, NREMT-P, & Kevin T. Collopy, BA, FP-C, CCEMT-P, NREMT-P, WEMT Photos by Art Hsieh, compliments of EMPACTonline.org 90 DECEMBER 2014 | EMSWORLD.com