Female preponderance in ibutilide-induced torsade de pointes

Abstract

Objective: Ibutilide, a class III antiarrhythmic agent used for pharmacological cardioversion of atrial arrhythmias, has a potential to cause QT-interval prolongation and torsade de pointes. Purpose of this study was to determine whether women are more prone to develop ibutilide-induced torsade de pointes. Methods: All clinical trials, cases, case series, and related articles in English-language in addition to 51 patients from our institution on the subject were examined. Results: In a database derived from 23 reports in literature and from our institution, 1720 patients received ibutilide for cardioversion of atrial arrhythmias. Only in 87% ( n=1492) patients, data were reported whether or not ibutilide caused torsade de pointes. The overall incidence of torsade de pointes was 3.9% ( n=58) patients. Data on sex distribution of ibutilide-induced torsade de pointes was available in 73% ( n=1096) patients. Torsade de pointes developed in 17 (5.6%) of 304 women and 24 (3%) of 792 men ( P=0.05). It occurred during or within 45 min after completion of the infusion of ibutilide. Treatment instituted was with intravenous magnesium sulfate alone in 14% ( n=8) patients, magnesium sulfate plus lidocaine in 5% ( n=3) patients, magnesium sulfate with electrical cardioversion in 17% ( n=10) patients, electrical cardioversion alone in 19% ( n=11) patients, and precordial thump in 3% ( n=2) patients. In 41% ( n=24) of patients who developed torsade de pointes, it resolved without treatment. There were no reported deaths secondary to torsade de pointes associated with ibutilide infusion. Conclusion: Incidence of ibutilide-induced torsade de pointes is higher in women than in men. Greater caution must be observed while using ibutilide in women.