Ablation of atrial fibrillation sources identified through sequential high-density mapping: in silico comparison...

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation, but recurrences are frequent. Ablating AF sources beyond PVI may prevent re-initiations. This proof-of-principle in silico study compares a novel source-based ablation approach to conventional strategies in preventing AF re-initiation.

We compared two conventional ablation strategies [PVI and PVI + posterior wall isolation (box ablation)] with our source-based approach. After PVI, a high-density mapping catheter was guided sequentially upstream of local repetitive conduction patterns until a source was identified. Located targets were ablated, connecting them to non-conducting boundaries. Strategies were compared based on their AF re-initiation rates after incremental pacing and ablated and electrically isolated areas. Analyses were performed in seven different scenarios with atria of different sizes, without (n = 3) and with fibrosis (n = 4), to assess different AF progression stages. Compared to no ablation, PVI reduced initiation rates in non-fibrotic atria (23 ± 8% control vs. 15 ± 0% PVI) but was less effective with fibrosis (60 ± 4% vs. 53 ± 10%). Box ablation was not superior to PVI while isolating more of the left atrium (isolated area in PVI: 31.5 ± 0.7% vs. box: 43.6 ± 0.5%). Conversely, source ablation completely prevented AF initiation in all scenarios, achieving comparable left atrial isolation with box ablation (isolated area without fibrosis: 36.3 ± 1.4%; with fibrosis: 43.2 ± 2.6%) and including right atrial lesions. Although macro-re-entrant tachycardias occurred frequently after source ablation, they were terminated with minimal lesions.

Ablating AF sources using our high-density mapping approach was more efficient in preventing AF re-initiation in silico than anatomy-based strategies.