title: An Unusual Case of Alternating Ventricular Morphology on the 12-Lead Electrocardiogram.
abstract: BACKGROUND
  One of the principal tasks of an emergency physician is identifying potentially life-threatening conditions in the undifferentiated patient; cardiac dysrhythmia is an example of such a condition. A systematic approach to a patient with atypical dysrhythmia enables proper identification of such-life threatening conditions.
  
  
  METHODS
  We describe a 31-year-old man presenting to the emergency department with an undifferentiated dysrhythmia after naloxone reversal of an opiate overdose. A systematic approach to the electrocardiogram led to the rare diagnosis of Wolff-Parkinson-White (WPW) alternans. We review the differential diagnosis of this dysrhythmia and the initial evaluation of a patient with the WPW pattern present on their electrocardiogram. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians should be prepared to use a systematic approach to an undifferentiated dysrhythmia to identify potentially life-threatening conditions.
authors.affiliation: Department of Emergency Medicine, Temple University, Philadelphia, Pennsylvania.
authors.forename: Maura
authors.initials: M
authors.lastname: Sammon
authors.affiliation: Department of Emergency Medicine, Temple University, Philadelphia, Pennsylvania.
authors.forename: Alveena
authors.initials: A
authors.lastname: Dawood
authors.affiliation: Department of Emergency Medicine, Temple University, Philadelphia, Pennsylvania.
authors.forename: Scott
authors.initials: S
authors.lastname: Beaudoin
authors.affiliation: Department of Emergency Medicine, Temple University, Philadelphia, Pennsylvania.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Harrigan
mesh_terms: D000328:Adult; D004562:Electrocardiography / Q000145:classification*; D004636:Emergency Service, Hospital / Q000458:organization & administration; D006329:Heart Conduction System / Q000002:abnormalities* / Q000503:physiopathology; D006556:Heroin Dependence / Q000150:complications; D006801:Humans; D008297:Male; D009270:Naloxone / Q000494:pharmacology / Q000627:therapeutic use; D009292:Narcotic Antagonists / Q000494:pharmacology / Q000627:therapeutic use; D014927:Wolff-Parkinson-White Syndrome / Q000175:diagnosis* / Q000503:physiopathology
chemical_list: D009292:Narcotic Antagonists; D009270:Naloxone
keywords: ECG; Wolff-Parkinson-White; dysrhythmia