Emergency Medical Services (EMS) Agency

ECG — October 2019


Paramedics respond to a 65-year-old homeless male with unknown past medical history.  He was found lying in a park unresponsive. 

Vital signs are blood pressure 115/78, HR 40, RR 8, O2 saturation 93%.

hypothermia1ECG obtained from LITFL



Rate:                                                  ~40 bpm

Rhythm:                                            Sinus Rhythm – p waves are difficult to discern due to baseline artifact                                                          but are noted prior to some QRS complexes.

ST Segment Elevation >1mm
In 2 or more contiguous Leads?:

Reciprocal Changes:                         N/A

Other Abnormalities:                        There is fine baseline artifact and a positive deflection
at the J point seen most obviously in leads V4 and V5.

This ECG pattern is consistent with hypothermia.  A variety of ECG findings may be found in a hypothermic patient.  Bradyarrhythmias (sinus bradycardia, atrial fibrillation with slow ventricular response, and AV blocks) are common.  Hypothermia may induce shivering resulting in fine baseline artifact as demonstrated on the ECG above.  A prolonged QT interval is another ECG finding in hypothermia.  A positive deflection of the J-point (a J wave, also known as an Osborn wave) can be seen in some cases too.

Figure 1.  The positive deflection at the J-point is a J-wave/Osborn-wave.


The height of the J-wave will have greater amplitude with increasing severity of hypothermia.

Hypothermic patients should be treated in accordance with TP-1223, Hypothermia/Cold Injury.  Warming measures including moving the patient to a warm environment, removing wet clothing, covering with blankets, and infusing warm normal saline (if available).  Given the patient’s unresponsiveness, he should also be treated in accordance with TP-1229, ALOC with an attempt to discern if there are any other underlying causes for his change in mental status (trauma, hypoglycemia, etc.). The patient should be transferred to the MAR for continued warming and further management.