Fluoroless high-density pulsed field vs radiofrequency ablation for atrial fibrillation guided by left atrial intracardiac echocardiography: The HALO protocol

BACKGROUND: Pulsed field ablation (PFA) is an alternative energy source to radiofrequency ablation (RFA) for atrial fibrillation (AF) with favorable safety and efficiency; however, outcomes are dependent on technique, lesion density, and tissue-contact assessment. OBJECTIVE: This study aimed to compare outcomes of AF ablation using PFA vs RFA when performed in an identical fluoroless workflow incorporating electroanatomic mapping and intracardiac echocardiography (ICE) using the high-density antral left atrial (LA) ICE-guided overlapping protocol. METHODS: This was a retrospective analysis of 192 patients undergoing AF ablation guided by LA ICE for contact assessment. PFA (n = 62) used high-density antral pulmonary vein overlapping lesions, whereas RFA (n = 130) combined ICE tissue enhancement with contact-force guidance. Lesion delivery was guided by spatial density and contact quality. RESULTS: Mean follow-up was 10.6 ± 4.3 months. Arrhythmia recurrence was lower with PFA (4.8%) than RFA (13.1%; 95% confidence interval, 0.09-1.15; P = .082). In paroxysmal AF, recurrence was significantly lower with PFA (2.1%) than RFA (15.8%; 95% confidence interval, 0.01-0.83; P = .011). In persistent AF, recurrence rates were similar (P = .569) despite a 3.5-fold higher proportion of redo procedures in the RFA group (P = .001) and more frequent posterior wall isolation in the PFA group (46.8% vs 20.8%; P < .001). Procedure duration was significantly shorter with PFA. No major complications occurred. CONCLUSION: In a standardized fluoroless high-density antral LA ICE-guided overlapping workflow, PFA achieved better short-term rhythm control in paroxysmal AF and significantly shorter procedure times. In persistent AF, outcomes were comparable with RFA. Lesion strategy and quality are critical determinants of ablation success beyond energy source selection alone.