Associazione Nazionale Medici Cardiologi Ospedalieri



Lock Protocol: a new robust workflow for a very high first pass pulmonary vein isolation during atrial fibrillation ablation

Zarra saveriS Pisa(Pisa) – AOUP

Introduction. Pulmonary vein isolation (PVI) is the gold standard for atrial fibrillation (AF) ablation. First pass PVI is often demanding when a raw geometry reconstruction is used in combination with an inaccurate automarks annotation, accounting for discontinuous or non-transmural lesions and related AF recurrences. We hypothesized that a magnetic-post processing of left atrial geometry in combination with an LSI-guided high power short duration (HPSD) automarks annotation could improve procedural efficiency.


Aim of the study was to determine the impact on procedural outcomes of the new “Lock PVI protocol” during AF ablation with the new voxel mode EnSite X mapping system.


We included in the study consecutive patients with AF scheduled for pulmonary vein isolation (PVI) at our Departement between January 2021 and December 2022. Patients were divided in two Groups, the Lock-PVI Group and the control No Lock-PVI Group. The “Lock PVI” Group was ablated with the new Ensite X System using the new protocol, which consisted in (1) performing a road map with contact-force annotation at potential PVI sites after High Density reconstruction, (2) shaving the magnetic geometry reconstruction to unearth true 3D location of contact points, (3) Use of 3D-Automarks color-coded with a Lesion Index (LSI) target of 5.5 (anterior) and 4.5 (posterior) (4) Inter-lesion distance £6 mm (5) High Power Short Duration Approach (50 W). The No-Lock PVI was represented by patients ablated with and HPSD ablation with the previous version of the EnSite Precision mapping suit as per local standard practice. Groups were compared in term of procedural duration, radiological exposure and “first pass” isolation.

Results. Forty-four patients (22 “Lock PVI” and 22 controls mean age 63,3±8 years, 65,9% male, 47,7% persistent AF), for a total of 88 PVI circles were enrolled. Procedural duration was similar between approaches (121,1±43,6 vs 125,3±30,1 min; P=0,72) but RF time was shorter in the “Lock PVI” group (19,6±4 vs 29,55±9,1 min; 0,001), even if with a longer fluoroscopy (19,5±10,1 vs 13,4±4,9 min; P=0,01). Of note, first pass isolation was significantly higher in the “Lock PVI” group: 40/44 (90,9%) vs 28/44 (63,6%) circles (P=0,002).

Conclusion. The new “Lock PVI” approach allowed a consistently better first pass isolation (>90%) with less RF time when compared to standard of care PVI.