A tailored substrate-based approach using focal pulsed field ablation in patients with symptomatic atrial fibrillation and advanced atrial substrate : Procedural data and 6-months success rates

Focal pulsed-field ablation (F-PFA) integrated in electroanatomical mapping (EAM) systems allows tailored lesion sets in patients with atrial fibrillation (AF) and advanced atrial cardiomyopathy.

To determine feasibility, safety and efficacy outcome of F-PFA for a tailored substrate-based catheter ablation (CA) approach in patients with AF and advanced atrial substrate.

We prospectively enrolled consecutive patients with AF and advanced atrial substrate treated by a F-PFA system (Cardiofocus) through contact-force sensing catheters integrated in EAM systems.

For substrate assessment, a high density mapping catheter was used. We defined an advanced substrate as the presence of prior AF ablation, presence of persistent AF and/or presence of significant left atrial scar (bipolar voltage <0,15mV).

The substrate-based tailored catheter ablation approach included isolation of all pulmonary veins (PVI) with wide area circumferential ablation (complete, partial or antralisation), posterior wall isolation (PWI), mitral anterior line (MAL) and cavo-tricuspid isthmus (CTI) ablation. Beyond this standard lesion set, ablation could be targeted on areas of focal fibrosis. The proposed workflow is presented in Figure 1.

We evaluated feasibility of these lesion sets as well as arrhythmia recurrence and safety at 6 months, respecting a 2 months blanking period.

83 patients were included (33% female, mean age 66 years, 80% persistent AF or atrial flutter (AFl), 57% re-do procedures, CHA²DS²VA 2.1±1.3, LAVI 44±15ml/m², time since first diagnosis 69 [32,107] months). 36 patients were first-do ablation and 47 patients re-do ablation.

Successful de-novo PVIs were performed in all 36 first-do patients and re-PVI in 30/47 re-do patients. Mitral anterior line was performed in 19 patients presenting atypical AFl and/or AF with anterior low voltage areas; PWI was performed in 38 patients with AF and low voltage areas or evoked delayed electrograms of posterior wall during premature atrial extrastimuli; CTI was performed in 24 patients for AF with associated typical AFl. Median procedural and fluoroscopy times were 115 and 7 minutes, respectively. Lesion set feasibility is presented in Figure 2A.

No major or minor complications occurred.

At 6 months, arrhythmia recurrence occurred in 30/83 patients (21 AF; 9 AFL), respecting a 2 months blanking period (Figure 2B). 8/9 patients with a recurrence during blanking had a late recurrence within 6 months of follow-up.

Tailored substrate-based F-PFA in patients with AF and atrial cardiomyopathy is safe and effective. Acute procedural success was 100% with 64% freedom from arrhythmias after 6 months.

Subtrate-based ablation approach