Tuesday, February 7, 2012

J-waves after ROSC and Intra-arrest Therapeutic Hypothermia

The following is the post-resuscitation 12-Lead electrocardiogram of an 82 year old female who received intra-arrest therapeutic hypothermia, via chilled saline and ice packs, as part of a new protocol for cardiac arrest management. The patient also received three defibrillations and was administered epinephrine, naloxone, and amiodarone during the resuscitation.

12-Lead ECG obtained approximately 5 minutes after ROSC
The post arrest 12-Lead ECG shows a sinus rhythm with frequent premature atrial and ventricular ectopic complexes. The LifePak 12, which uses the GE Marquette 12SL algorithm, displayed the ominous *** ACUTE MI SUSPECTED *** message and suggested a lateral injury pattern.

Closer inspection of the lateral precordial leads reveals the ST-elevations present are actually giant J-waves, or Osborn waves.

J-waves--or Osborn waves--appreciated in the lateral precordial leads
Recognizing this finding is present, a closer look at the entire 12-Lead ECG shows that subtle J-waves are present in almost every lead group.

Subsequent 12-Lead ECG obtained 17 minutes after ROSC
A repeat 12-Lead ECG acquired 12 minutes later shows a sinus tachycardia with a single PAC, without the giant J-waves from the initial ECG, diffuse ST/T-wave changes consistent with ischemia are also present. However, small J-point elevation persists in the lateral precordials. The computerized interpretation no longer believes a STEMI-pattern is present and incorrectly identifies the rhythm as atrial fibrillation.

Comparison of the precordial leads between the first and subsequent 12-Lead ECG.
A side by side look at the precordial leads provides an interesting look at the near resolution of the giant J-waves post-ROSC.

One explanation for the normalization of the traditional electrocardiographic findings of hypothermia may be related to the management of the patient's ventilation both intra-arrest and post-arrest. As the patient's pH normalized with mechanical ventilation and a perfusing rhythm, so did the repolarization abnormalities (visualized as J-waves).

  1. Antzelevitch C, Yan GX. J Wave Syndromes. Heart Rhythm. 2010; 7(4):549-558. [FullText]
  2. Fenstad ER, et al. Therapeutic hypothermia in out of hospital sudden cardiac arrest: Significance of J-waves. J Am Coll Cardio. 2011; 57(14):Suppl 5, E1002. [PDF FullText]
  3. Edelman ER, Joynt K. J Waves of Osborn Revisited. J Am Coll Cardio. 2010; 55(20):2287. [PubMed]
  4. Dr. Smith's ECG Blog: Osborn Waves and Hypothermia.