Antiarrhythmic drugs cut atrial high-rates episode burden, AF risk

Individuals with atrial high-rates episodes (AHREs) are at greater risk of progression to atrial fibrillation (AF). But the good news is that treatment with antiarrhythmic medication appears to have a protective effect both on AHRE burden and AF risk.

In a randomized clinical trial involving patients with AHRE duration ≥24 hours, as detected by dual-chamber pacemakers, the primary endpoint of progression to clinical AF occurred with significantly less frequency in the groups of patients who received antiarrhythmics (IC antiarrhythmics, 20.37 percent; beta-blockers, 25.86 percent; amiodarone, 8.77 percent) than in the control group (36.23 percent; p<0.001) during a mean follow-up of 20.84 months. [Simovic S, et al, EHRA 2023]

“Average time to clinical AF progression was significantly longer in groups of patients treated with antiarrhythmics (IC antiarrhythmics, beta-blockers and amiodarone) than in the control group (17.7, 17.2, and 19.0 vs 15.9 months, respectively; p<0.001),” said lead study author Dr Stefan Simovic, from the University of Kragujevac, Kragujevac, Serbia, who presented the results at EHRA 2023.

The Kaplan-Meier plot showed that among the antiarrhythmic medications, amiodarone significantly prolonged the time to clinical AF progression compared with beta-blockers (p=0.017) but only showed a trend toward longer time to progression when compared with IC antiarrhythmics (p=0.057). No significant between-group difference was seen between IC antiarrhythmics and beta-blockers (p=0.567).

As for the secondary endpoint, AHRE burden was likewise significantly lower in the antiarrhythmic group than in the control group (6.9 percent vs 15.4 percent; p<0.001). Consistent with the primary endpoint finding, amiodarone showed superiority in lowering AHRE burden when compared with IC antiarrhythmics and beta-blockers (2.1 percent vs 5.6 percent and 7.8 percent, respectively; p<0.001), while no significant differences were observed between IC antiarrhythmics and beta-blockers (p=0.18).

The study included a total of 307 patients (mean age 71.4 years, 54.07 percent women), who were randomly assigned to the intervention group (n=169) or the control group (n=138). Of those in the intervention group, 54 received IC antiarrhythmics, 58 received beta-blockers, and 57 received amiodarone. The baseline patient characteristics were generally similar in the study groups.

It is important to talk about AHRE, given its association with not only progression to clinical AF but also with increased risks of major adverse cardiovascular events, mortality, and stroke and systemic embolism, according to Simovic. [Sci Rep 2021;11:5753; JACC Clin Electrophysiol 2019;5:1197-1208; N Engl J Med  2012;366:120-129]

“Although oral anticoagulation should be initiated in patients with CHADs-VASc score ≥2 and episode duration ≥24 hours, treatment of AHRE with antiarrhythmics” is not widely investigated, he noted.

Based on the present data, Simovic pointed out that antiarrhythmics are beneficial in that they help lower AHRE burden and duration, as well as slow down progression to AF.

“Randomized clinical trials are needed to investigate further the early antiarrhythmic treatment of AHRE without clinical AF,” he added.