Catheter Ablation -> Atrial Fibrillation & Atrial Flutter: -> Clinical Trials / Outcomes D-PO03 - Poster Session III (ID 48) Poster

D-PO03-172 - Paroxysmal Af With High Vs Low Arrhythmia Burden:atrial Remodeling And Ablation Outcome (ID 1515)


Background: The relation between atrial tachyarrhythmia (ATA) burden in paroxysmal atrial fibrillation (AF), atrial remodeling and efficacy of catheter ablation (CA) is unknown
Objective: 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: ATA burden, defined as the % 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. CA efficacy was assessed by reduction in ATA burden and 1-year freedom from any ATA.
Results: 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). CA reduced ATA burden by 100% [100-100] in both groups (p=1.0). Freedom from any ATA after CA was equally high (83% vs 89%, p=0.38)(Fig.1).
Conclusion: Paroxysmal AF patients with high ATA burden have altered LA mechanical properties, reflected by larger size and impaired function. Despite mechanical remodeling of the atria, they are excellent responders to CA. Most likely the lack of fibrosis explains why pulmonary veins remain the dominant trigger for AF in this patient cohort.