The J wave in accidental hypothermia.

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.