BACKGROUND - Atrial fibrillation and atrial flutter (AF/AFL) are the most common arrhythmias encountered in clinical practice. Rate versus rhythm control remains a difficult decision, especially in the acute setting. Ibutilide is a class III antiarrhythmic indicated for pharmacological cardioversion of recent-onset AF/AFL. At the University of Texas MD Anderson Cancer Center, restoration of sinus rhythm is desirable because many patients have contraindications to anticoagulation. In addition, most are on multiple medications that prolong the QT interval; therefore, the objective of this study was to establish the safety and efficacy of ibutilide.
METHODS - This was a retrospective chart review of 81 patients who were identified via the pharmacy database as receiving ibutilide for AF/AFL from January 2002 to May 2006. Outcomes including cardioversion rates and effects on the QT interval were recorded.
RESULTS - Ibutilide use was associated with successful cardioversion in 75% of patients. Out of 81 patients, 68 patients (84%) were on at least 1 medication that prolonged the QT interval at the time of ibutilide administration. However, no significant changes in the corrected QT interval pre and post ibutilide cardioversion were noted in any group of patients.
CONCLUSIONS - Overall, ibutilide is safe and effective in cancer patients when used for acute cardioversion of AF/AFL. Despite the use of multiple medications that can potentially prolong the QT interval, no patient experienced serious life-threatening rhythm disturbances or significant QT prolongation during ibutilide administration.