Magnesium treatment of torsade de pointes--a case report.

An eighty-one-year-old woman received quinidine in order to convert atrial fibrillation to a sinus rhythm. The patient developed a prolonged QT interval on the EKG, as well as episodes of torsade de pointes. With the administration of intravenous magnesium sulfate, the abnormal rhythm was suppressed within minutes. Thus, magnesium should be the first drug used in patients with torsade de pointes and prolonged QT interval on the electrocardiogram.