The chef preparing your holiday meal is found in the kitchen unresponsive. He is taken to the ED and this is his EKG:

What happened?

As it turns out, the chef was so hot on this balmy Christmas Eve, that he decided to take a quick nap break in the freezer room.  The EKG above is tricky because it may look like Digoxin toxicity or even hyperkalemia; however, there are undeniable Osborn waves (J waves) which are consistent with hypothermia. At body temperatures below 32°C, there is decreased firing of the cardiac pacemaker cells resulting in bradycardia and Osborn waves on EKG (upward deflection at the end of the QRS complex). Verdict is still out on why they appear, but it is surmised that they may represent abnormal ion flux in cold temperatures along with delayed depolarization and early repolarization of the left ventricular wall. With more profound hypothermia, Osborn waves get bigger and intervals begin to stretch out in the following order: PR, followed by QRS and then QTc. Hypothermia may also cause arrhythmias, the most common of which is atrial fibrillation. If the patient is not responding after adequate rewarming, be concerned for other ingestions (alcohol, benzo), endocrine emergency, sepsis.

With some warm IV fluids, warms blankets, and some holiday spirit love, the chef makes a miraculous recovery and will never sleep in the freezer room again.

Sources:

EM Crit

FOAMcast