Atrial fibrillation (AF) is commonly categorized as paroxysmal AF (PAF) or persistent AF (PeAF); however, this binary classification may not adequately reflect arrhythmia burden or predict post-ablation outcomes. This study, published in EP Europace, assessed whether pre-procedural AF burden, defined as the percentage of time spent in AF, is associated with recurrence following AF ablation.

A total of 302 patients scheduled for AF ablation were included (mean age 64±9 years; 33% female), comprising 67% with PAF and 33% with PeAF. Prior to ablation, participants underwent structured rhythm monitoring using 60-second single-lead ECG recordings three times daily, supplemented by symptom-triggered recordings, over a four-week period. AF burden was calculated as the proportion of monitored days with documented AF. The primary endpoint was AF recurrence between 3 and 12 months post-ablation.

At 12 months, recurrence rates were significantly higher in PeAF compared with PAF (37.6% vs. 24.4%, p=0.01). Similarly, patients with higher AF burden (>32%) had higher recurrence rates compared with those with lower burden (≤32%) (36.4% vs. 24.0%, p<0.01). Notably, PAF patients with higher AF burden demonstrated recurrence rates comparable to PeAF. Pre-procedural AF burden was independently associated with recurrence (HR 1.06; 95% CI 1.0-1.1; p=0.025).

These findings suggest that AF burden may provide additional information beyond conventional classification.