Related Experiment Videos
The J wave in accidental hypothermia
Insights
J waves on electrocardiograms are common in accidental hypothermia, often linked to lower body temperatures. These J waves may persist even after rewarming, making diagnosis challenging.
Area of Science:
- Cardiology
- Emergency Medicine
- Physiology
Background:
- Accidental hypothermia presents significant diagnostic challenges.
- Electrocardiogram (ECG) abnormalities are common in hypothermia.
- The J wave, an ECG finding, has been anecdotally associated with hypothermia.
Purpose of the Study:
- To investigate the prevalence and characteristics of J waves in patients with accidental hypothermia.
- To determine the relationship between J waves and body temperature, ECG lead location, and arterial pH.
Main Methods:
- Retrospective review of ECGs from 50 patients with accidental hypothermia.
- Analysis of J wave presence, prominence, and size in relation to recorded body temperature and other clinical parameters.
Main Results:
- J waves were observed in 80% (40/50) of hypothermia patients.
- J waves were most frequent in leads II or V6, but prominent in V3 or V4 during deep hypothermia.
- J wave size correlated with body temperature, being larger below 30°C and smaller above.
- J waves persisted in some patients even after rewarming, mimicking normal ECG variations.
Conclusions:
- J waves are a frequent ECG finding in accidental hypothermia, particularly at lower body temperatures.
- The size and prominence of J waves vary with body temperature and ECG lead.
- Persistent J waves post-rewarming can complicate ECG interpretation in hypothermia survivors.
Abstract:
Electrocardiograms of 50 patients with accidental hypothermia were reviewed with regard to the J wave with the following results: (1) J waves were observed in 40 of 50 cases. (2) J waves were recorded most frequently in leads II or V6 (34 of 40 cases, 85%). However, in deep hypothermia, the J wave was often most prominent in leads V3 or V4. (3) The size of the J wave appeared to be related to body temperature. Below 30 degrees C, large J waves were often observed; above 30 degrees C, J waves were usually smaller. (4) J waves were not distinctive in the cases with clockwise rotation. (5) The appearance and the size of the J waves seemed not to be associated with the arterial pH. (6) The J wave decreased in size along with rise of the body temperature. However, a small J wave persisted in many cases even after normothermia was restored. It was also difficult to distinguish these small J waves from small notches at the QRS-ST junction which are sometimes observed in normal individuals not subjected to hypothermia.