Discerning the Incidence of Symptomatic and Asymptomatic Episodes of Atrial Fibrillation Before and After Catheter Ablation (DISCERN AF): A Prospective, Multicenter Study
How common are asymptomatic episodes of atrial fibrillation (AF) in patients who undergo catheter ablation (CA) for symptomatic AF?
In the DISCERN AF study (Discerning Symptomatic and Asymptomatic Episodes Pre and Post Radiofrequency Ablation of Atrial Fibrillation), 50 patients (mean age 57 years) with symptomatic AF received an implantable loop recorder (ILR) at least 3 months before undergoing CA. The patients were asked to keep a symptom diary. The ILR data were downloaded and diaries were reviewed prior to CA and at 3, 6, 9, 12, 15, and 18 months post-CA.
The mean AF burden was 2.0 hours/day/patient pre-CA and decreased significantly to 0.3 hours/day/patient post-CA. Complete freedom from symptomatic AF was achieved by CA in 58% of patients. Six patients (12%) had only asymptomatic episodes of AF post-CA. Fifty-two percent of AF episodes were asymptomatic pre-CA. This proportion increased significantly to 79% post-CA. Independent predictors of asymptomatic AF included CA, shorter duration and slower rate of AF episodes, and lower heart rate variability.
Asymptomatic episodes of AF are common in patients with symptomatic AF undergoing CA, and approximately 10% of patients have only asymptomatic episodes of AF post-CA.
The study confirms that the efficacy of CA of AF cannot accurately be determined based on symptoms alone. The possible reasons that a higher proportion of AF episodes are asymptomatic after CA than beforehand include a placebo effect of CA, a reduction in the duration of AF episodes, and/or atrial autonomic denervation.
Keywords: Incidence, Placebo Effect, Autonomic Denervation, Atrial Fibrillation, Bradycardia, Heart Rate, Catheter Ablation
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