Paroxysmal atrial fibrillation with high vs. low arrhythmia burden: atrial remodelling and ablation outcome

The relation between atrial tachyarrhythmia (ATA) burden in paroxysmal atrial fibrillation (AF), atrial remodelling, and efficacy of catheter ablation (CA) is unknown. We investigated whether high vs. low-burden paroxysmal AF patients have distinct clinical characteristics or electro-mechanical properties of the left atrium (LA) and whether burden impacts outcome of CA. Atrial tachyarrhythmia burden, defined as the percentage of time spent in ATA, was assessed by insertable cardiac monitors in 105 patients before and after CA. Clinical characteristics and electro-mechanical properties of LA were compared between patients with high vs. low ATA burden. Catheter ablation efficacy was assessed by reduction in ATA burden and 1-year freedom from any ATA. Median ATA burden was 2.7% (highest tertile 9.3%). Clinical characteristics and electrical properties of LA (refractoriness, conduction velocity, low voltage) did not differ between high (≥9.3%) vs. low ATA burden (