Clinical Significance of J Waves in Patients Undergoing Therapeutic Hypothermia for Out-of-Hospital Cardiac Arrest

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.