Although Osborn waves are a marker of hypothermia, they also occur in nonhypothermic conditions. Brainstem death is a precursor of the J wave, and this is explained by impaired thermoregulatory ability resulting from hypothalamic dysfunction and subsequent hypothermia.
The three electrocardiograms presented here illustrate several points:
- Classic findings in hypothermia include J waves, sinus bradycardia, prolongation of the PR interval, widening of the QRS complex, and prolongation of the QT interval.
- The lower the core body temperature, the higher the amplitude of the J wave.
- The J wave in brain death (unlike hypothermic causes of the J wave) is not associated with the characteristic signs of shivering in the surface electrocardiogram.
- As hypothermia becomes more profound, the J wave becomes evident in all leads, not only the inferolateral leads.