Quant Imaging Med Surg. 2026 Oct 1;16(10):794. doi: 10.21037/qims-2026-0593. Epub 2026 Sep 18.
ABSTRACT
BACKGROUND: Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for paroxysmal atrial fibrillation (PAF). The ablation index (AI) provides an estimate of lesion size and depth, but does not definitively confirm transmurality. Complete elimination of the negative component of the unipolar electrogram (UPE) has been proposed as a marker of transmural lesion formation. High-power short-duration (HPSD) radiofrequency ablation (RFA) produces more homogeneous lesions with clearer boundaries and thus may be more suitable for PVI. This study aimed to assess the AI values achieved during PVI using UPE-guided HPSD RFA and to compare the efficacy and safety of UPE-guided vs. fixed AI-guided HPSD RFA in patients with PAF.
METHODS: A total of 276 patients with PAF were randomly assigned to two groups: the UPE group and the AI group. In the UPE group (n=136), the ablation endpoint for each lesion was defined as continuation of ablation for 2 seconds after conversion of the UPE morphology from RS to R. In the AI group (n=140), the ablation endpoint for each lesion was achievement of a predefined target AI value (400-450 for the anterior wall and 360-380 for the posterior wall). The pulmonary vein (PV) first-pass isolation rate, acute PV reconnection (APVR) rate, and atrial fibrillation (AF) recurrence rate were compared between groups.
RESULTS: The AI values were significantly lower in the UPE group than in the AI group (P<0.001). The inter-lesion distance (ILD) was significantly greater in the UPE group than in the AI group (P<0.001). The left and right PV first-pass isolation rates were higher in the UPE group (93.4% vs. 85.0%, P=0.03; and 95.6% vs. 89.3%, P=0.048, respectively). APVR occurred less frequently in the UPE group than in the AI group (11.0% vs. 20.0%, P=0.040). At 12 months post-procedure, AF recurrence was observed in 13 patients (9.6%) in the UPE group and 14 patients (10.0%) in the AI group (P=0.902). Three patients in the UPE group and four patients in the AI group developed inguinal hematoma (2.2% vs. 2.9%, P>0.99).
CONCLUSIONS: Both UPE-guided and AI-guided HPSD RFA were effective and safe in patients with PAF. UPE-guided ablation was associated with lower AI values, higher PV first-pass isolation rates, and a lower incidence of APVR. These findings suggest that UPE-guided HPSD RFA may provide a more individualized approach to PVI than fixed AI-guided ablation alone.
PMID:42861152 | PMC:PMC13654110 | DOI:10.21037/qims-2026-0593