Ibutilide in persistent atrial fibrillation refractory to conventional cardioversion methods

Background: Electrical cardioversion of atrial fibrillation seems to be enhanced by pretreatment with ibutilide, but only few is known about the effects of ibutilide in atrial fibrillation which failed to convert with class III antiarrhythmic agents and electrical cardioversion. The objectives of this study were to evaluate the efficacy and safety of ibutilide administration in patients with persistent atrial fibrillation refractory to long-term therapy with class III antiarrhythmic drugs and transthoracic cardioversion. Methods: Prospective study in 22 patients (16 men and 6 women, mean age 63±9 years) with structural heart disease and persistent atrial fibrillation for a mean duration of 39±50 (range 1-145) months. All patients had failed to convert to sinus rhythm after transthoracic cardioversion while on treatment with class III antiarrhythmic drugs (amiodarone in 82%, sotalol in 18%). One milligram of ibutilide was administered in all patients and electrical cardioversion was performed again, if necessary. Results: The total conversion rate to sinus rhythm was 95% (21 of 22 patients). Two patients (9%) were successfully converted after ibutilide alone and 19 patients (86%) when transthoracic cardioversion was repeated after ibutilide. The QTc intervals increased from 451±28 to 491±49 ms (p<0.001) after ibutilide. No adverse effects occurred. The rate of freedom from atrial fibrillation after 1 month of follow-up was 64%. Conclusions: The efficacy of concomitant use of ibutilide infusion and, if necessary, repeated transthoracic cardioversion for restoration of sinus rhythm in long-term persistent atrial fibrillation and previously failed antiarrhythmic and electrical cardioversion was 95%. There were no adverse effects associated with ibutilde administration. Our results suggest that this combined strategy may be safe and successful in patients with atrial fibrillation resistant to conventional cardioversion methods and may be an alternative to internal cardioversion.