Dronedarone better than sotalol in post-AF ablation setting

Treatment with dronedarone following atrial fibrillation (AF) ablation appears to lead to a reduced risk of cardiovascular hospitalization as well as lower rates of combined proarrhythmia when compared with sotalol, as shown in a recent study.

“This is the first study to demonstrate a difference in the effectiveness and safety of specific antiarrhythmic therapy other than amiodarone in the postablation setting,” according to the investigators.

In a propensity‐score matched cohort of 1,815 patients who received dronedarone and 1,815 of those who were given sotalol after AF ablation, the former showed a 23–30 percent lower risk of cardiovascular hospitalization at 3 months (adjusted hazard ratio [aHR], 0.77, 95 percent confidence interval [CI], 0.61–0.97), 6 months (aHR, 0.76, 95 percent CI, 0.63–0.93), and 12 months (aHR, 0.70, 95 percent CI, 0.66–0.93). There was no between-group difference in the risk of repeat ablation and cardioversion. [J Am Heart Assoc 2022;doi:10.1161/JAHA.120.020506]

Compared with sotalol, dronedarone also had a much better safety profile, with a lower risk of proarrhythmia at 3 months (aHR, 0.76, 95 percent CI, 0.64–0.90), 6 months (aHR, 0.80, 95 percent CI, 0.70–0.93), and 12 months (aHR, 0.83, 95 percent CI, 0.73–0.94) after ablation.

The reduced risk of cardiovascular hospitalization with dronedarone, according to the investigators, was predominantly attributable to lower rates of atrial tachyarrhythmias‐related hospitalization. The greater relative efficacy of the drug as opposed to sotalol may explain this difference, although there may be other factors in play, including potentially better rate control and lesser symptoms during AF because of stronger antidromotropic effects and/or greater concomitant use of arterioventricular nodal blocking agents because of lesser concern about drug‐induced bradycardia with dronedarone.

Meanwhile, the dominant driving factor for the difference in the proarrhythmia composite at 3, 6, and 12 months was the increased risk of bradyarrhythmias and pacemaker implantation with sotalol, consistent with the known bradycardic effects of the drug, the investigators pointed out. [Card Electrophysiol Clin 2016;8:437-452; Eur Heart J 2020;42:373-498]

“The higher incidence of significant bradycardia and pacemaker implantation in the recovery phase with sotalol compared with dronedarone in our study raises concern that acute changes after ablation may alter the safety profile of a drug,” they noted.

“Antral or wide circumferential ablations of the pulmonary veins cause autonomic dysfunction, resulting in higher resting and exercise heart rates in the first few months after ablation. This may provide some protection from the bradycardic effects of sotalol in the recovery phase after ablation. Once this attenuates, the bradycardic effects of sotalol may become more pronounced to necessitate pacemaker implantation,” the investigators explained. [Circulation 2004;109:327-334]

They, however, acknowledged that other confounding factors, such as a higher incidence of sinus node dysfunction after superior vena cava isolation or ablation of foci along the superior crista terminalis, could not be excluded.

The study had several limitations, including failure to determine the type or duration of AF, the progression pattern of AF, and the type of AF ablation from the database, which possibly affected propensity score–matching balance. Despite these, the investigators concluded that dronedarone may be a more effective and safer alternative than sotalol in the post-AF ablation setting.

“Further research is warranted on the treatment effects between dronedarone and sotalol adjunctive to ablation, including results on mortality. Moreover, [analysing] ablation type, other antiarrhythmic drugs, and persistence of use may provide more information on treatment choices for a wider array of clinical considerations,” they said.