Stroke volume changes during focal pulsed field vs. radiofrequency ablation for ventricular substrate using Sphere-9 catheter assessed by arterial waveform analysis: a prospective case series

Abstract Aims Catheter ablation using radiofrequency (RF) or pulsed field (PF) energy is an effective treatment method for ventricular arrhythmia (VA). PF offers advantages in lesion formation in anatomically challenging regions. However, its acute effects on ventricular contractility during substrate modification require further elucidation. This study aimed to compare real-time hemodynamic changes associated with PF versus radiofrequency ablation in the left ventricle using stroke volume (SV) as a surrogate for myocardial response in regard to the safety of multiple lesion delivery within scarred myocardium. Methods and results We conducted a prospective case series study of eight consecutive patients undergoing VA ablation using a dual-energy lattice-tip catheter (Sphere-9, Medtronic). Lesions were delivered to scarred regions identified via intracardiac echocardiography (ICE) and high-resolution 3D mapping. Hemodynamic monitoring was performed using a minimally invasive arterial waveform system (HemoSphere, Edwards Lifesciences). A total of 317 PFA and 41 RF lesions were delivered. PFA applications were associated with a transient SV reduction of 33.1±8.3 ml, with normalization post-delivery. RF lesions resulted in a minimal SV change (≤10% from baseline value). SV reduction following PFA was consistent across lesion locations. All patients achieved post-procedural non-inducibility of clinical VT. Conclusion PF causes transient but reversible reductions in LV stroke volume during lesion delivery, likely reflecting acute electroporation-induced myocyte stunning rather than irreversible dysfunction. RF lesions did not produce similar changes. These findings suggest a favorable safety profile for PF in ventricular substrate ablation, including in cases of multiple lesion sets, and support its use in regions of scarring. Further studies are warranted to validate these observations and assess long-term outcomes.