Acute efficacy and safety of cryoballoon versus pentaspline pulsed field ablation catheter for superior vena cava isolation: insights from two prospective registries

Background Superior vena cava isolation (SVCI) is an adjunctive strategy for managing atrial fibrillation by targeting non-pulmonary vein triggers. Although the cryoballoon (CB) is used off-label for SVCI, its application is limited by risks of phrenic nerve and sinus node injury. The novel pentaspline pulsed field ablation (PFA) catheter provides a nonthermal, tissue-selective alternative. A direct comparison of their acute efficacy and safety in SVCI is lacking. Purpose To compare the procedural characteristics, acute efficacy, and safety of empirical SVCI using CB versus a pentaspline PFA catheter. Methods Data from two institutional prospective registries of patients with paroxysmal AF undergoing first-time pulmonary vein isolation with adjunctive empirical SVCI were pooled and analyzed. The primary efficacy endpoint was acute SVCI. The primary safety endpoint was a composite of all periprocedural complications. Results A total of 107 patients were analyzed (CB, n=75; PFA, n=32). Baseline demographic characteristics were similar between groups (mean age 62.7±10.1 vs. 62.7±8.7 years, p=0.873; 64% vs. 59.4% male, p=0.668). Other key baseline characteristics and comorbidity rates did not differ significantly. Acute SVCI was achieved in 82.7% (62/75) of CB and 93.8% (30/32) of PFA cases (p=0.34). Procedure duration was significantly shorter with PFA (44.5 min, IQR 35-60) compared with CB (52.5 min, IQR 45-65; p=0.004). However, fluoroscopy time was significatly shorter with CB (5 min, IQR 4-8) than with PFA (8 min, IQR 7-11) min; p<0.001). Nevertheless, total radiation dose did not differ significantly between groups (CB: 6 mGy, IQR 3.25-21.5 vs. PFA: 7 mGy, IQR 4-24.25; p=0.74), likely because cine acquisition was used exclusively during CB procedures, whereas only standard fluoroscopy was used with PFA. Major complications were rare (CB 2.6%, PFA 0%; p = 1.0). One CB patient required permanent AAI pacemaker implantation for sinus node injury, and another required surgical repair of a vascular complication (pseudoaneurysm with arteriovenous fistula). Phrenic nerve palsy (PNP) occurred in 26 CB patients (34.7%), predominantly during SVC ablation (24/26, 82.8%), with all cases impending or transient. No PNP occurred with PFA group (p<0.001). Bradycardia or junctional rhythm during SVC ablation occurred in 15 (20%) CB patients versus 2 (6.3%) PFA patients (p=0.09). Conclusion CB and pentaspline PFA catheter demonstrated comparable acute efficacy for SVCI. However, PFA enabled shorter procedures and was associated with a more favorable safety profile, with no phrenic nerve or sinus node injury observed. These findings support PFA as a promising and safer modality for adjunctive SVCI in AF ablation.