Prognostic Value of J (Osborne) Waves on ECG tracing during Mild Therapeutic Hypothermia in Patients after Out of Hospital Cardiac Arrest (JOW trial).

Patients (pts) admitted to the hospital after successful resuscitation of sudden cardiac death (SCD) are treated with therapeutic hypothermia of 33⁰C for 24 hours to facilitate brain preservation. The implications of the presence of J (Osborne) waves (JOW) in 12 leads ECG in this setting has not yet been studied. These patients may exhibit a number of coexisting conditions in addition to hypothermia that can influence the electrical activity of myocardial membranes, such as brain injury, cardiac ischemia, sedatives and electrolyte imbalance.

The aim of the study:
was to ascertain the prognostic significance of JOW recorded during 33°C therapeutic hypothermia in SCD survivors, based on retrospective analysis of the records of all patients treated with hypothermia in our hospital.

Methods:
55 consecutive pts (22% females, mean age 58.6±12.5 y.o.) who underwent therapeutic hypothermia between 01/2011 and 11/2016 in our department were included in this study. We compared pts with JOW (33 pts) to pts without JOW (22 pts). Mean follow-up was 35.7±20.9 months.

Results:
The pts with JOW compared to pts without JOW were younger (55.1±11.6 vs 64.5±11.7 y.o., p<0.006), with a lower incidence of hypertension (52% vs 86%, p<0.007), diabetes mellitus (15% vs 50%, p<0.005) and congestive heart failure (15% vs 45%, p<0.013). In-hospital and long term mortality were significantly higher in pts without JOW (86% vs 21%, 91% vs 24% accordingly, p<0.000001). No patient without JOW was treated with implantable cardioverter defibrillator compared to 27% of the pts with JOW. In pts without JOW, 66.7% of patients suffered from post-hospital irreversible brain injury vs 7.7% of pts with JOW (p<0.0001). The incidence of JOW among survivors was 93% vs 29% among pts who died (p<0.00001).

Conclusions:
The absence of J (Osborne) wave on ECG during therapeutic hypothermia is a powerful predictor of poor prognosis among SCD survivors.