A large footprint catheter toggling between pulsed field and radiofrequency energy: first clinical experience for inappropriate sinus node tachycardia ablation

A novel sinus node (SAN) sparing hybrid ablation for inappropriate sinus node tachycardia (IST)/Postural Orthostatic Tachycardia Syndrome (POTS) has been demonstrated to be an effective and safe therapeutic option in patients with symptomatic drug-resistant IST/POTS.

The mapping and ablation lattice-tip catheter can toggle between pulsed field (PF) and radiofrequency energy. Recent clinical studies have demonstrated the efficacy and safety of the lattice-tip catheter for ablation of supraventricular and ventricular tachycardias. However, there are no clinical studies in the setting of IST ablation and hybrid thoracoscopic ablation.

The aim of this study is to evaluate the feasibility, efficacy and safety of the lattice-tip catheter in the context of: (1) hybrid SAN sparing ablation and (2) redo after hybrid procedure.

All consecutive patients with: 1) Diagnosis of symptomatic IST, refractory or intolerant to drugs and 2) IST ablation procedure performed with the lattice-tip catheter were included. Ablation procedures were: 1) index hybrid SAN sparing ablation or 2) redo ablation after hybrid procedure. The primary endpoint was freedom from any arrhythmia.

A total of 11 patients were included, 3 patients (27.3%) underwent an index hybrid SAN sparing ablation and 8 patients (72.7%) underwent a redo procedure. Hybrid procedures were all performed with a zero-fluoroscopy approach and an epicardial thoracoscopic map of the SAN was successfully performed after endocardial mapping in all patients, Figure 1. Crista terminalis (CT) line was completed with endocardial PF ablation in 2/3 patients, Figure 2. Indication for redo procedure was: IST recurrence in 4/8 patients and other supraventricular arrhythmias in 4/8 patients (junctional tachycardia in 1 patient, typical atrial flutter in 1 patient, atrial tachycardia in 1 patient and atrial fibrillation in 1 patient). At redo procedures, lesion set was as follows: SVC re-isolation in 2/8 patients, IVC re-isolation in 3/8 patients, CT line in 2/8 patients, cavo-tricuspid isthmus in 2/8 patients, pulmonary vein isolation in 2/8 patients, junctional tachycardia ablation in 1/8 patients and SAN ablation with pacemaker implantation in 1/8 patients.

At a median follow-up of 8 months, 2/8 patients had IST recurrence. No complications were observed.

In a cohort of patients undergoing IST ablation, the novel lattice-tip catheter was effective and safe with versatility in treating supraventricular tachycardias at redo IST ablation.

Notably, this study is the first to report the successful implementation of a zero-fluoroscopy approach and epicardial thoracoscopic mapping using the lattice-tip catheter, that are feasible in a clinical setting.Figure 1  Figure 2