Hypothermia is a medical emergency that occurs when your body loses heat faster than it can produce it, causing a dangerously low body temperature.
Occurs when body temperature falls below 35 °C.
Left untreated, hypothermia can lead to complete failure of the cardiovascular and respiratory system and eventually to death.
- Mild hypothermia is 32-35 °C
- Moderate hypothermia is 29-32 °C
- Severe hypothermia is < 29 °C
- excessive shivering, weak pulse, slowed breathing, slowed speech, clumsiness or lack of coordination, confusion or memory loss
- shivering artefact
- prolonged PR interval, QRS and QT interval
- Osborn waves (J waves) - a positive deflection at the J point (negative in aVR and V1), most prominent in inferior and precordial leads; the height is roughly proportional to the degree of hypothermia
- ectopic activity -> atrial fibrillation
If temperature below 30°C
If temperature below 28°C
- cardiac arrest due to VT, VF or asystole
Picture 1 Osborn wave
ECG 1A Patient after CPR before targeted temperature management (only atrial fibrillation present)
ECG 1B Patient during targeted temperature management (34° C) - slower rate of atrial fibrillation, ST elevations with incipient Osborn waves (II, III, aVF, V5-V6), prolonged QT interval.
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- Levis JT. ECG Diagnosis: Hypothermia. Perm J. 2010;14(3):73. doi:10.7812/tpp/10-087
- Mareedu RK, Grandhe NP, Gangineni S, Quinn DL. Classic EKG changes of hypothermia. Clin Med Res. 2008;6(3-4):107-108. doi:10.3121/cmr.2008.809