High power short duration and very high power short duration protocol: a comparison between two effective strategies of atrial fibrillation transcatheter ablation with radiofrequency
Authors: Grandin R , D'angelo L , Compagnucci P , Parisi Q , Cipolletta L , Molini S , Rita E , Valeri Y , Campanelli F , Pirani F , Luciani L , Castellucci G , Cardinali F , Casella M , Dello Russo A 
Published: May 2024

Abstract

Introduction
Radiofrequency (RF) is the most widely used technique for atrial fibrillation (AF) ablation. Aiming to achieve durable pulmonary vein isolation (PVI) with reduced procedural time and potential thermal side effects, high power short duration (HPSD) and very-high power short duration (v-HPSD) protocols have been developed, exploiting the use of the latest catheter generations.

Purpose
To assess safety and efficacy of AF ablation using two distinct HPSD settings, aiming to determine the most effective protocol for trans-catheter RF AF ablation.

Methods
We conducted a retrospective study including patients with paroxysmal or persistent AF: 100 were treated with the HPSD protocol and 100 patients with the v-HPSD one. In the HPSD protocol, RF energy at 40 W was applied for up to 20 seconds for the anterior segments of the pulmonary vein (PV), and 50 W up to 10 seconds for the posterior segments of the PV and the posterior wall (PW). Conversely, in the v-HPSD protocol RF pulses were applied at 50 W with an ablation index (AI) 500 in the anterior segments of PV and 90 W up to 4 sec for the posterior segment of the PV and the PW. Safety and efficacy were assessed during the procedure, during the hospital stay and throughout the entire follow-up duration.

Results
No relevant clinical and echocardiographic differences were identified between the two groups. Successful PVI and PW isolation was achieved in all cases. The v-HPSD group demonstrated a higher first-pass isolation (FPI) rate compared to the HPSD group. In contrast, the HPSD group exhibited a greater impedance drop (ID), supported by a higher contact force (CF). The RF total time, the procedural time, and the dose-area product (DAP) were significantly lower in the v-HPSD group. No periprocedural complications were reported. During the follow-up no significant differences in AF recurrence rates have been observed.

Conclusions
The absence of procedural complications underscores the high safety of both protocols. In our study, the v-HPSD group exhibited a superior FPI rate, indicative of enhanced acute efficacy; however it is crucial to underline that the HPSD group included a higher proportion of patients with a history of prior AF ablation. The more elevated ID observed in the HPSD group, indicating the exceptional quality of lesions, could be related to the major conductive heating component compared to v-HPSD. This results in deeper lesions and a more significant ID. Conversely, the brief duration of applications in the v-HPSD protocol contributes to reduce procedural times and diminish radiation exposure. Despite procedural disparities, the follow-up period reveals a low recurrence rate of AF in both groups, emphasizing the effectiveness of both HPSD and v-HPSD protocols in AF treatment.Kaplan-Meier Curve