Real-World Comparison of Fixed- vs. Variable-Loop Circular Pulsed Field Ablation Catheters During Clinical Implementation: Acute Procedural Outcomes

Background:

Pulsed field ablation (PFA) has emerged as a promising non-thermal technique for pulmonary vein isolation (PVI) in atrial fibrillation (AF). With the introduction of the fixed-loop circular catheter (FLCC; PulseSelect™, Medtronic) and the variable-loop circular catheter (VLCC; Varipulse™, Johnson & Johnson), two novel circular PFA systems have become available for clinical use. However, no real-world comparative data exist, and date on ablation beyond PVI are sparse.

Objective:
The aim of the study is to compare acute efficacy, procedural characteristics, and safety of PVI and non-PV ablation between patients treated with FLCC versus VLCC during the early implementation phase of both PFA systems in real-world setting.

Methods:

A total of 90 consecutive patients were included, comprising the first 45 cases performed with each PFA system. All procedures were performed under general anesthesia or deep conscious sedation. FLCC procedures were performed under fluoroscopic guidance, while VLCC was integrated into a 3D mapping system, reflecting standard real-world use of each catheter. Additional ablation beyond PVI was performed at the operator’s discretion based on clinical and electroanatomic findings. Acute outcomes regarding acute efficacy and safety were assessed and compared between groups. Procedural times were analyzed separately in the PVI-only cohort to ensure comparability.

Results:

In the FLCC group (n=45), 30 patients underwent PVI-only, while 15 received additional ablation (12 roof lines, 1 posterior wall isolation, 2 cavotricuspid isthmus [CTI] ablations). In the VLCC group (n=45), 28 patients received PVI-only, and 17 underwent additional ablation (10 posterior wall isolations including 2 superior vena cava isolations, 1 mitral isthmus line, 4 CTI ablations, and 3 roof lines). Two VLCC cases were repeat AF ablations. All other cases were first AF ablation procedures. Acute PVI success was 100% in both groups. Bidirectional conduction block was achieved across all additional ablation lines. All ablations were performed without the need for additional radiofrequency touch-up applications. The median number of applications (IQR) performed at each ablation site using both systems is presented in Table 1.

Regarding PVI-only cases procedural times were longer in VLCC group, including median total skin-to-skin time (67.2 min vs. 76 min, p < 0.01) and LA-dwell time a (47 min vs. 58 min, p < 0.01). However, the median fluoroscopy time was shorter (11.4 min vs. 8.3 min, p < 0.01). 

No significant differences in complication rates were observed between the groups (p = 0.62). In the VLCC group, one patient experienced two complications (transient ST-segment elevation and stroke), and another patient had one minor vascular complication. In the FLCC group, one patient experienced a minor vascular complication. The observed complications were not directly device-related.

Conclusion:

This study represents a real-world comparison of two circular PFA catheter systems for PVI and additional ablation beyond PVI during their clinical implementation. The FLCC and VLCC systems were both associated with high acute efficacy and favorable safety outcomes for PVI as well as adjunctive ablation procedures. FLCC was associated with shorter overall procedural time, while VLCC offered reduced fluoroscopy exposure. Further studies are warranted to evaluate long-term outcomes and durability of lesion sets created by these PFA systems.