title: Clinical Significance of J Waves in Patients Undergoing Therapeutic Hypothermia for Out-of-Hospital Cardiac Arrest.
abstract: BACKGROUND
  Hypothermia is associated with the development of J waves. However, little is known about the impact of these electrocardiogram (ECG) findings on the development of ventricular arrhythmias and patient outcomes during therapeutic hypothermia (TH) postresuscitation from out-of-hospital cardiac arrest (OHCA). We investigated the prevalence of J waves in OHCA patients prior to and during TH. Additionally, we explored the incidence of atrial and ventricular arrhythmias and in-hospital mortality for patients with and without J waves either at baseline, during TH, or both.
  
  
  METHODS
  We conducted a retrospective analysis of patients who suffered OHCA and underwent TH (goal temperature of 32-34°C). Fifty-nine patients were stratified dependent upon the presence of or the development of J waves on surface ECGs. Descriptive analysis and logistic regression modeling were used to assess the population differences and mortality, respectively, between patients who developed J waves during TH and those who did not.
  
  
  RESULTS
  There was no difference in the development of in-hospital atrial or ventricular arrhythmias between patients with J waves present during TH (16%) and those without (17.6%, P = 0.834). Compared to patients without J waves at baseline and during TH, those with J waves present both at baseline and during TH had significantly worse survival (hazard ratio = 12.42, P = 0.046).
  
  
  CONCLUSIONS
  While J waves are common ECG findings during TH in patients resuscitated from OHCA, our study demonstrated an increase in mortality for patients with J waves present both at baseline and during TH.
authors.affiliation: Department of Medicine, Morristown Medical Center, Morristown, New Jersey.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Harhash
authors.affiliation: Gussak Consulting LLC, Morristown, New Jersey.
authors.forename: Ihor
authors.initials: I
authors.lastname: Gussak
authors.affiliation: Department of Medicine, Morristown Medical Center, Morristown, New Jersey.
authors.forename: James
authors.initials: J
authors.lastname: Cassuto
authors.affiliation: Department of Cardiovascular Medicine, Morristown Medical Center, Morristown, New Jersey.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Winters
mesh_terms: D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000209:etiology*; D004562:Electrocardiography / Q000379:methods*; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D006323:Heart Arrest / Q000175:diagnosis / Q000517:prevention & control*; D006801:Humans; D007036:Hypothermia, Induced / Q000009:adverse effects* / Q000379:methods; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: J waves; early repolarization; out-of-hospital cardiac arrest; target temperature management; therapeutic hypothermia