Prominent J wave (Osborn wave) with coincidental hypothermia in a 64-year-old woman.

A 12-lead electrocardiogram (ECG) was obtained in a 64-year-old woman whose body temperature was 32°C. The ECG showed sinus bradycardia with a prolonged PR interval, a prolonged QRS complex, a prolonged QT interval, and a prominent J wave that was distinguishable in all leads (Fig. 1). Forty-eight hours later, after the patient had been rewarmed to 37°C, an ECG showed progressive normalization of the sinus rate, QT normalization, and a decrease in the amplitude and duration of the J waves (Fig. 2). Fig. 1 A 12-lead electrocardiogram obtained at a body temperature of 32°C. Note Osborn waves, which have an extra deflection at the end of the QRS complex. Fig. 2 A 12-lead electrocardiogram obtained 48 hours later—after rewarming of the patient to 37°C—is normal. Osborn waves, also known as J waves, camel-hump waves, or hypothermic waves, are best seen in the inferior and lateral precordial leads. They become more prominent as the body temperature decreases, and they resolve gradually with rewarming.1