Lesion Delivery and Scar Formation in Catheter Ablation for Atrial Fibrillation The DECAAF II Trial.

BACKGROUND

The DECAAF-II randomized trial showed no difference in AF recurrence with additional delayed enhancement MRI (DE-MRI) fibrosis-targeted ablation to pulmonary vein isolation (PVI) in persistent AF.

OBJECTIVES

We evaluated the impact of lesion delivery on ablation-induced scarring and AF recurrence.

METHODS

Lesions delivered, targeting fibrotic and non-fibrotic areas identified from pre-ablation DE-MRI, were studied in relation to ablation-induced scarring on 3-months DE-MRI, including their association with arrhythmia recurrence.

RESULTS

593 patients, treated with radiofrequency were analyzed: 293 underwent PVI and 300 underwent additional fibrosis-guided ablation. Lesion analysis showed that 80.9% in the MRI fibrosis-guided group vs 16.5% in the PVI group (p<0.001), had ≥ 40% of baseline fibrosis targeted. MRI assessment of ablation-induced scar showed that 44.8% of fibrosis-guided ablation and 15.5% of PVI had ≥ 40% of their fibrosis covered by scar (P<0.001), demonstrating a significant attenuation from lesions delivered to scar formed. In the overall population, fibrosis coverage with scar was not associated with recurrence (HR 0.90, 95% confidence interval [CI] 0.80-1.01, p = 0.08 per 20% increase). In patients with baseline fibrosis <20%, fibrosis coverage with scar was associated with lower recurrence than PVI (HR 0.85; 95% CI [0.73-0.97]; p=0.03), whereas the association was not significant when baseline fibrosis ≥20% (HR 0.97; [0.80-1.17], p=0.77). Significant center variation was observed in fibrosis targeting and coverage with scarring.

CONCLUSIONS

Radiofrequency ablation lesions do not uniformly result in scar formation. Post hoc analysis suggests reduced arrhythmia recurrence when ablation-induced scarring covers fibrotic regions in patients with low baseline fibrosis.

Informations de copyright

Copyright © 2024. Published by Elsevier Inc.