Polymorphous ventricular tachycardia associated with a marked prolongation of the Q-T interval induced by amiodarone.

We report the case of a patient who developed a life-threatening polymorphous ventricular tachycardia ( PVT ) after six weeks of treatment with amiodarone. The Q-T interval was markedly prolonged at 0.86 second. The drug induction of PVT was strongly suggested by the fact that PVT resolved four days after withdrawal of amiodarone when the Q-T interval had shortened to 0.60 second; the arrhythmia has not recurred in the nine months of follow-up since then. Amiodarone, though a very effective antiarrhythmic agent, may induce serious PVT .