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Prominent J Wave in Accidental Hypothermia

      An 81-year-old man with a history of schizophrenia was found unconscious and was admitted to our hospital. On admission, his temperature was lower than 33°C. Electrocardiography showed regular bradycardia (heart rate, 46 beats/min) and prolonged QT interval of 560 ms. Prominent J wave (arrows) and ST-segment elevation were observed in almost all leads. Warming was initiated immediately after admission. Within 1 hour, the patient's temperature had increased to 33.4°C, and the amplitude of the J wave had decreased. Eleven hours later, his temperature had increased to 35.0°C, and consciousness had returned to normal. The J wave disappeared, but the ST segment remained elevated. Twentyone hours later, the patient's temperature had returned to normal, and J-wave and ST-segment elevation had disappeared. In this case, gradual resolutions of J-wave and ST-segment elevation were observed during treatment with warming.