SAN FRANCISCO — Giving antiarrhythmic medications in the 6 weeks after ablation for atrial fibrillation cut the rate of clinically significant arrhythmias and the need for cardioversion or hospitalization.
The Antiarrhythmics After Ablation of Atrial Fibrillation (5A) study findings provide the first evidence to support prescribing antiarrhythmics to reduce arrhythmias occuring after ablation, and were contrary to expectations, Dr. Jean-Francois Roux said at the annual meeting of the Heart Rhythm Society. He said he has no association with companies making the medications studied.
The trial was halted early after data on 110 of a planned 160 patients showed significant benefits from the postprocedure antiarrhythmics. The nonblinded study randomized 53 patients undergoing ablation to start antiarrhythmia therapy the night of the procedure, using propafenone or flecainide for those with structural heart disease, or dofetilide or sotalol if they had heart disease. The other 57 received only atrioventricular nodal blocking agents after ablation.
Nine patients (17%) in the antiarrhythmics group and 23 (40%) in the control group developed clinically significant atrial arrhythmias or couldn't tolerate the medications, said Dr. Roux of the University of Pennsylvania, Philadelphia, and associates. Significant arrhythmias were defined as atrial fibrillation for more than 24 hours, arrhythmias requiring initiating or changing antiarrhythmic medication, or arrhythmia-related hospitalizations or electrical cardioversions.
Patients were monitored transtelephonically for 4 weeks postablation and seen 6 weeks after the procedure. Their mean age was 55 years; 71% were men. The groups' baseline characteristics were similar, with an average left atrial size of 4.2 cm, normal left ventricular ejection fractions, and prior atrial fibrillation for an average of 71 months in the medication group and 81 months in the controls. Before ablation, around 94% of patients used antiarrhythmic therapy, and 25% of each group had undergone previous atrial ablation. Three patients in the treated group stopped therapy due to side effects such as severe fatigue, rash, and headaches.
Using the end points of arrhythmias for more than 24 hours or cardioversion or hospitalization for arrhythmia, rates still were significantly lower in the treated group (6 patients; 11%), compared with the control group (15; 26%). Patients will be tracked for 6 and 12 months to see how the postablation therapy affects long-term arrhythmia rates.
Patients treated with amiodarone in the 3 months before ablation were excluded. A separate study compares postablation therapy with amiodarone or dronedarone.