Giant J wave on 12-lead electrocardiogram in hypothermia.

Findings on standard 12-lead electrocardiogram in patients with hypothermia include sinus bradycardia, prolonged QT and PR interval, wide QRS complex, supraventricular and ventricular arrhythmia, and the most striking electrocardiographic abnormality, the J wave. Although characteristic of hypothermia, J wave also occurs in other conditions. The electro-physiologic basis of J wave in hypothermia has been recently elucidated. We present a case of giant J wave due to accidental hypothermia and in addition discuss the features, mechanism, and significance of J wave in hypothermia.