Voltage threshold adjustments for a novel pulsed-field ablation catheter with integrated mapping capabilities: lessons from a case series.

Background: Accurate electroanatomical mapping relies on voltage thresholds to differentiate electrically inactive areas, fibrotic scar, and healthy myocardium. These thresholds have been well established for high-density mapping catheters with small, closely spaced electrodes. However, the optimal voltage thresholds for a novel pulsed-field ablation catheter with integrated mapping capabilities remain unclear. This case series evaluates different voltage thresholds for the variable-loop circular catheter (VLCC, Varipulse, Biosense Webster) compared with a dedicated high-density mapping catheter (Octaray, Biosense Webster).

Case Summary: Four patients undergoing left atrial catheter ablation-including pulmonary vein isolation (PVI), posterior wall ablation, and ablation for scar-related atrial flutter-were mapped using both the VLCC and Octaray catheter. The key findings include: (i) standard voltage thresholds for high-density catheters overestimate voltage in scarred and ablated tissue when applied to the VLCC, necessitating adjusted voltage settings; (ii) the VLCC effectively identified PVI and reconnections, posterior wall isolation, anterior wall scarring, and atrial flutter circuits; and (iii) while the VLCC identified areas of scar, its representation remained less precise compared with high-density mapping.

Discussion: This case series demonstrates that the VLCC provides satisfactory mapping performance in common use cases but requires voltage threshold adjustments for accurate visualization. Despite its ability to detect ablation endpoints, scar characterization remains less accurate. Further quantitative analysis of electrogram differences and a prospective evaluation in a larger patient population are necessary to determine the optimal voltage thresholds for this catheter.