Right atrial substrate ablation for persistent atrial fibrillation is associated with higher atrial tachycardia recurrence: proarrhythmic effect or distinct substrate?

Background Catheter ablation (CA) is a well-established treatment for paroxysmal atrial fibrillation (AF), but its efficacy in persistent AF remains limited. To enhance outcomes, substrate modification is often added to pulmonary vein isolation, though the optimal strategy for persistent AF ablation is still under debate. Electrographic flow mapping (EGF) and dipole charge density mapping (AcQMap) are emerging technologies that enable comprehensive atrial mapping and identification of AF sources. This study evaluated the impact of targeted substrate ablation guided by EGF and AcQMap on recurrence rates of AF and atrial tachycardias (ATs). Methods We analyzed data from 85 patients undergoing substrate ablation (SA) for persistent AF using either EGF (n=40) or AcQMap (n=45). Procedural metrics included procedure duration, fluoroscopy exposure, and radiofrequency (RF) application. Outcomes were assessed based on recurrence of AF and AT. Results The mean patient age was 62.8±8.6 years, with 66.3% male. Average procedure time was 182.6±48.4 minutes, RF ablation time 1917.0±939.9 seconds, RF applications 32.0 (IQR 19.0–45.5), and fluoroscopy dose 256.0 (IQR 169.5–408.0) mGy. Substrate ablation was performed in the left atrium (LA-SA) in 65 patients and in both atria (BiA-SA) in 20 patients. BiA-SA procedures were significantly longer than LA-SA (212.9 vs. 173.3 minutes, p<0.01). AF recurrence occurred in 24.7% of patients, with no significant difference between LA-SA and BiA-SA groups (23.1% vs. 30.0%, p=0.53). However, AT recurrence was notably higher in the BiA-SA group (50.0%) compared to LA-SA (13.8%, p<0.001). Mean time to AT recurrence was 10.7±9.1 months. Six patients required repeat procedures for AT, with no RA-origin ATs observed in the LA-SA group. Conclusion While AF recurrence rates did not differ significantly between LA-only and biatrial substrate ablation, targeting right atrial substrates was associated with a markedly higher rate of AT recurrence and longer procedure times. These findings suggest that biatrial ablation may have a proarrhythmic effect in patients with persistent AF.