Grid annotation vs. ablation tags in predicting lesion area coverage for pulmonary vein isolation using a variable-loop circular catheter

Background: The Variable-Loop Circular Catheter (VLCC) is a bidirectional multi-electrode catheter capable of electroanatomical mapping and pulsed field energy delivery for the treatment of atrial fibrillation (AF). Objective: to compare Grid projected annotation (GRID) versus projected Ablation tags (ABLt) in predicting lesion area coverage for Pulmonary Vein Isolation (PVI) with VLCC. Methods: Consecutive patients with AF who underwent PVI with VLCC were prospectively enrolled in our center between April 2024 and October 2024. Ablation area was visualized using projected 1 mm3 grid points (GRID) or 2 mm projected ablation tags (ABLt) corresponding to each VLCC electrode for every ablation. Bipolar voltage maps were performed with VLCC to quantify the lesion areas per PV segment (10-segment model) after PVI. Anatomical maps with GRID or ABLt annotation without voltage data were used to calculate predicted lesion area. The predictive capability of GRID/ABLt was calculated using the formula GRID or ABLt Area in Low Voltage Area/ Total Low Voltage Area and expressed as a percentage. Results: We enrolled 32 patients (63.6 ± 10.2 years, 50% males, 28.1% Persistent AF) and a total of 130 PVs. All patients underwent PVI. Median procedural time was 60 min (50-90), dwelling time 30 min (25-50) and fluoroscopy time 5 min (3-10). GRID and ABLt annotations were consistent with PV lesion area resulting in a Pearson's correlation coefficient of 0.90 (p < 0.0001) and 0.84 (p < 0.0001), respectively. GRID showed a higher predictive capability of overall PV lesion area compared to ABLt (95.8% vs 77.6%; p