Effects of antiarrhythmics on atrial high rate episodes and progression to clinical atrial fibrillation (ANTI-AHRE)

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Atrial High Rates Episodes (AHRE) are associated with progression to clinical atrial fibrillation (AF), stroke, increased risk of MACE and increased mortality (1-4). Although oral anticoagulation should be initiated in patients with CHADs-VASc score ≥ 2 and episode duration ≥ 24h, treatment of AHRE with antiarrhythmics was not investigated so far. PURPOSE: This study aimed to assess the effects of antiarrhythmic treatment on AHRE and its impact on the progression to clinical AF and AHRE burden. METHODS: This study included patients with AHRE duration ≥ 24h detected by dual-chamber pacemakers, without a previous diagnosis of AF and treatment with antiarrhythmics. Nominal settings with high atrial rate criterion programmed to 200 beats/min were used for AHRE detection. Patients were randomized to the Intervention (n=169) and Control Group (n=138). Patients in the Intervention Group received antiarrhythmic treatment (Ic antiarrhythmics (n=54), beta-blockers (n=58) and amiodarone (n=57)). The primary endpoint was progression to clinical AF and the secondary endpoint was AHRE burden. RESULTS: A total of 307 were included in the study, with a mean age of 71.4±8.15, 166 (54.07%) females and a mean follow-up 20.84±5.04 months. The baseline characteristics did not differ significantly between groups. During the follow-up, 50 patients (36.23%) from the Control group developed clinical AF. In groups of patients treated with Ic antiarrhythmics, beta-blockers and amiodarone, clinical AF developed in 11 (20.37%), 25 (25.86%) and 5 (8.77%) patients, respectively (p<0.001). Average time to clinical AF progression was significantly longer in groups of patients treated with antiarrhythmics (Ic antiarrhythmics, beta-blockers and amiodarone) compared to the Control group (17.7, 17.2, 19.0 vs 15.9 months, respectively, p<0.001). The Kaplan-Meier plot of freedom from clinical AF is given in Figure 1. Amiodarone prolonged the time to clinical AF progression significantly compared to beta-blockers (p=0.017), while a trend was observed compared to Ic antiarrhythmics (p=0.057). No significant differences between Ic antiarrhythmics and beta-blockers were observed in time to clinical AF progression (p=0.567). The AHRE burden was significantly lower in the Intervention group compared to the Control group (6.9% vs 15.4%, p<0.001). Amiodarone was superior in lowering the AHRE burden when compared to Ic antiarrhythmics and beta-blockers (2.1% vs 5.6% and 7.8%, respectively, p<0.001), while no significant differences were observed between Ic antiarrhythmics and beta-blockers (p=0.18) CONCLUSION: Initiating antiarrhythmics for AHRE episodes leads to a lower AHRE burden and progression to clinical AF. Randomized clinical trials are needed to investigate further the early antiarrhythmic treatment of AHRE without clinical AF. [Figure: see text]