The olive strategy: a novel ablation protocol for pulmonary vein isolation with the pentaspline pulsed field catheter

Background: Pulsed field ablation (PFA) is a novel non-thermal energy source for cardiac ablation which especially stands out through selectively damaging cardiomyocytes while sparing the surrounding tissue. The pentaspline PFA catheter is increasingly used for pulmonary vein isolation (PVI). Its shape can be seamlessly changed between different configurations. While large international registries as well as a randomized controlled trial with this device show non-inferiority in comparison to conventional thermal ablation, PFA has on the other hand not yet succeeded in reducing arrhythmia recurrence. An increasing amount of remapping data suggest, that PVI durability has room for improvement. To attempt such improvement, we added additional applications with a new catheter configuration to the standard ablation protocol.

Methods: The conventional pentaspline PFA catheter ablation protocol consists of 8 applications per pulmonary vein (PV): 4 in a flower configuration and 4 in a basket configuration. We added two additional applications per PV in a smaller ‘olive-configuration’. This configuration leads to a catheter position slightly more protruded towards the ostium of the PV as compared to the antral positions of the flower- and basket-configuration. We present procedural data, early clinical outcome data as well as first remapping data of this new ablation protocol.

 

Results: 312 patients were treated with the olive-strategy (OLIVE). They are compared to 660 patients who were treated before with the conventional strategy (CONV). Patients who underwent additional ablation beyond PVI were excluded from this analysis. Patient baseline characteristics showed no significant difference (OLIVE vs CONV: Age 67.1 vs 67.9; male 64.2% vs 61.9%; BMI: 27.4 vs 27.9; paroxysmal AF 62.9% vs 62.1%; LA diameter 41.04 mm vs 42.09 mm; median CHA2DS2-VASc-Score 2 for both). Procedure time (33.86 min vs 33.74 min) and fluoroscopy time (7.43 min vis 7.01 min) did not increase significantly due to the additional applications. 

The 6-month follow-up has been completed by 63 OLIVE patients so far. Freedom of arrythmia at 6 months was 81%. Of these patients, 4.8% took antiarrhythmic drugs at the time of the follow-up visit. 

To date, 7 of the OLIVE patients and 51 of the CONV patients underwent a repeat ablation for recurrent arrhythmia. PV reconnections were found in one of the OLIVE patients, who had a reconnection of the left inferior and right inferior PV. PV angiograms were performed in all 7 patients, and none showed signs of PV stenosis. The overall rate of reconnected PVs of OLIVE vs CONV is 7.1% vs 19.1% (p = 0.19).

Conclusion: We present an extension of the standard ablation protocol with the pentaspline PFA catheter. The OLIVE strategy is safe and effective and does not prolong the procedure. In a small number of repeat procedures, a trend towards less PV reconnections in comparison to patients treated with the CONV strategy can be observed, but a higher number of remapping procedures is needed to potentially reveal a statistically significant effect. Additionally, more and longer clinical follow-up data is needed and will be available at the time of presentation.