Very high-power short duration ablation metrics predictors of successful pulmonary vein isolation in atrial fibrillation ablation

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Abstract Background Previous studies have shown that very high-power short duration (vHPSD) is a safe ablation modality, with similar rate of first pass isolation (FPI) but faster ablation times compared to standard CLOSE protocol guided ablation. While CLOSE protocol uses ablation index to guide energy titration no such index exists for vHPSD ablations yet. Purpose Our aim was to evaluate ablation metrics as predictors of FPI in atrial fibrillation ablation (AF) using vHPSD ablation modality. Methods In a single centre retrospective analysis, we analysed consecutive patients treated for paroxysmal (PAF) or persistent atrial fibrillation (PeAF) with PVI using vHPSD ablation from May 2021 to January 2023. We excluded patients with previous PVI procedures. The analysis was done via a cloud-based commercially available ablation analysis tool CARTONET. We analysed catheter stability, average contact force, absolute impedance drop, number of ablations and cumulative ablation time in relation to first pass isolation (FAAVI – first attempt all veins isolated). Results This is the first larger data study to evaluate ablation metrics in vHPSD using commercially available CARTONET (Figure 1). Based on the inclusion criteria 150 patients were included in the analysis. Baseline characteristics and procedural metrics are presented in Figure 2 - Table. We observed a numerical trend towards higher FAAVI rate with increasing patients number (p=0.10). Complication rate was low (1 pericardial effusion requiring drainage and 1 vascular access site complication). Ablation metrics analysis yielded statistical differences between FAAVI and no FAAVI groups (Figure 2 - Table). Multivariate analysis identified average contact force (odds ratio (OR) 1.001; 95% confidence interval (CI): 0.999-1.003; p=0.047) and catheter stability (OR 0.985; 95% CI: 0.973-0.997; p=0.019) to be independent predictors of FAAVI. Additionally, number of applications (OR 1.000; 95% CI: 0.999-1.000; p=0.042) and total ablation time (OR 0.995; 95% CI: 0.991-0.999; p=0.021) were also independent predictors of FAAVI, possibly indicating larger vein and/or ablation circumferent line to be predictive of no FAAVI. Catheter stability of less than 1.16mm (AUC 0.61; p=0.015) was shown to be discriminative of FAAVI, however discrimination value was poor. Average contact force was not discriminative of FAAVI (AUC 0.58; p=0.105) in our patient cohort. Conclusion Average contact force and catheter stability were predictive of first pass isolation, however only catheter stability was discriminative of FAAVI. Larger data with standardised ablation protocol (interlesion distance) and wider range of ablation metrics is needed to corroborate and further build on these early findings.