Very early experience with the new dual energy pulsed field/ radiofrequency catheter with contact force measurement for point-by point ablation of ventricular arrhythmias

A new dual energy catheter allows toggling between radiofrequency ablation (RFA) and pulsed field ablation (PFA) while performing point-by-point ablation. In vitro experimental studies showed that using PF and RF-applications at the same region has the potential to create deeper lesions than RF alone. We present our initial experience with this catheter in ablation cases of premature ventricular contractions (PVC) or ventricular tachycardias (VT).

Methods: Patients undergoing a redo ablation for PVC/ VT or with presumably intramural substrate underwent ablation with the DE catheter. Before ablation in close vicinity (<1-2 cm) to coronary vessels 2 mg nitroglycerine was administered, followed by further applications in longer lasting PF ablations. Ablation in close vicinity to mechanical heart valve (<5 mm) was avoided because of manufacturer warnings. Furthermore close to the His (<5 mm) no PF applications were performed. Basic clinical and intra-procedural data were collected, all patients will undergo 6 months follow up examination. In PVC cases complete success was defined as elimination of the dominating PVC morphology and partial success as a reduction in PVC burden by >50% during the procedure. In VT cases complete success was defined as non-inducibility of any VT and partial success as non-inducibility of the clinical VT.

Results: Eleven patients (4 with PVC ablation, 7 with VT ablation) were included until now. The patients were 68 ±8 years old, in 73% male. Non ischemic cardiomypathy was present in 64%, Amyloidosis in 9%, valular cardiomyopathy in 9% and structurally normal hearts in 18%. LVEF was 41 ±15%. Mean procedure time was 98 ±27 min for PVC and 135 ±29 min for VT.

In the PVC cohort considering safety precautions only 2 patients were finally ablated with PFA on RF, one with partial and one with complete success. Both were redo cases.

The VT cases had a mean 2.9 previous ablations. In 5/7 patients VTs could be induced before ablation. Complete success was reached in 5/7 patients, partial success in 1/7.

In one PVC case we observed a prolonged triggered VT during PF ablation that does not terminate under ablation, but within one minute after ablation. In one VT case with septal substrate AV-block occurred. However, no PF applications were done near the conduction system. No other complications were noticed. Six months follow up results are pending, but the data will be presented at the EHRA congress.

Conclusion: Considering some precautions PF on RF ablation for PVC or VT using the new Dual energy point by point ablation catheter seem to be safe and effective. Larger cohorts have to be examined before final conclusions and acute reactions under PF ablation have to be further evaluated.