Amiodarone and hypokalemia. A dangerous combination.

We describe the appearance of long QT interval and polymorphous ventricular tachycardia in a patient treated with amiodarone who presented with hypokalemia secondary to chronic diuretic therapy. Ventricular pacing was initiated upon admission. The hypokalemia was corrected and amiodarone was discontinued. After three days the patient showed a normal QT interval and was free of ventricular tachyarrhythmias. Although hypokalemia could itself have been the arrhythmogenic factor in this particular patient, the additional toxic effect of amiodarone cannot be ruled out. It seems reasonable to consider the combination of both as dangerous when we take into account that the majority of patients cited as having amiodarone-induced torsade de pointes had also potassium depletion.