Induced hypothermia: electrocardiographic abnormalities.

Hypothermia was induced intermittently in a patient to combat hyperpyrexia. The electrocardiogram taken during the hypothermic phase displayed typical abnormalities and consisted of: pronounced sinus bradycardia, marked prolongation of the Q-T interval, muscle tremor artifact, and the characteristic "Osborn wave." Spontaneous rewarming resulted in disappearance of the electrocardiographic alterations, underscoring the functional and reversible nature of the abnormalities.