A 25-year-old man was found comatose in a park in August, 1993, and was taken to hospital by the fire department. He was hypotensive and could not follow commands, although localising neurological findings were absent. His heart rate varied between 30 and 250 beats per min. Intravenous lines were placed and the patient was taken to intensive care. The initial electrocardiogram (ECG; lead II) is shown in the figure. The patient was intubated and defibrillated twice at 200 J, with no change in his ECG. Epinephrine, norepinephrine, atropine, and lidocaine were all infused without effect. Intermittent asystole necessitated cardiopulmonary resuscitation. A pacemaker was placed but there was no response from his heart. Over the next 7 h, he received almost continuous chest compression and numerous attempts at cardioversion. Naloxone had no effect. Initial blood values included pO2 660 mm Hg, pCO2 25 mm Hg, pH 7·29 (with FiO2 at 100%), bicarbonate 11 mmol/L, sodium 133 mmol/L, potassium 2·9 mmol/L, chloride 97 mmol/L, and creatinine 125 mol/L. Potassium, sodium bicarbonate, volume expanders, and furosemide were given with no improvement. Poisoning was suspected, although no poisons were found. Activated charcoal and magnesium sulphate were given via a nasogastric tube after gastric lavage.