Key result
Catheter ablation achieved equally high 1-year freedom from atrial tachyarrhythmia in paroxysmal AF patients with high versus low arrhythmia burden (83% vs. 89%, P=0.38).
Why the study?
The relation between atrial tachyarrhythmia burden in paroxysmal AF, atrial remodelling, and catheter ablation efficacy was unknown.
Does catheter ablation reduce atrial tachyarrhythmia burden equally in paroxysmal AF patients with high versus low arrhythmia burden?
Cohort (n=105)
Does catheter ablation reduce atrial tachyarrhythmia burden equally in paroxysmal AF patients with high versus low arrhythmia burden?
Paroxysmal AF patients with high arrhythmia burden have altered left atrial mechanical properties but respond equally well to catheter ablation compared to those with low burden.
Supports ablation consideration across burden levels in paroxysmal AF despite LA changes; leaves open need for randomized confirmation.
AIMS: 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. METHODS AND RESULTS: 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 (<9.3%) patients. High ATA burden patients had larger LA diameter (46.5 ± 6 vs. 42.5 ± 6mm, P < 0.01), volume (93.8 ± 22 vs. 80.4 ± 21mL, P = 0.01), and lower LA reservoir and contractile strain (19.7 ± 6 vs. 24.7 ± 6%, P < 0.01; 10.3 ± 3 vs. 12.8 ± 4%, P = 0.01). Catheter ablation reduced ATA burden by 100% (100-100) in both groups (P = 1.0). Freedom from ATA after CA was equally high (83% vs. 89%, P = 0.38). CONCLUSION: Paroxysmal AF patients with high ATA burden have altered LA mechanical properties, reflected by larger size and impaired function. Despite mechanical remodelling of the atria, they are excellent responders to CA. Most likely the lack of fibrosis and/or advanced electrical remodelling explain why pulmonary veins remain the dominant trigger for AF in this patient cohort.
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Strisciuglio et al. (2020) conducted a cohort in Paroxysmal atrial fibrillation (n=105). Catheter ablation in high ATA burden (≥9.3%) vs. Catheter ablation in low ATA burden (<9.3%) was evaluated on 1-year freedom from any atrial tachyarrhythmia (p=0.38). Catheter ablation achieved equally high 1-year freedom from atrial tachyarrhythmia in paroxysmal AF patients with high versus low arrhythmia burden (83% vs. 89%, P=0.38).
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