Systematic use of automatic high-density late annotation mapping for ventricular tachycardia ablation procedures - The SLAM-VT study

Background Ventricular tachycardia (VT) is a common arrhythmia in patients with structural heart disease. Catheter ablation of VT is effective but critically depends on accurately identifying the arrhythmogenic area. Traditionally, manual annotation of late potentials—crucial identifiers of such areas—has resulted in cumbersome processes with high operator variability. A Late Annotation Mapping (LAM) module was integrated into the CARTO 3 Mapping system to automate late potential annotation and address these limitations. This multicenter observational study directly compares LAM with the Legacy Wavefront (WF) technique regarding diagnostic capabilities, standardization, and clinical outcomes. Methods The SLAM-VT study was a retrospective multicenter analysis involving patients undergoing VT ablation from 31 European sites. Procedural data were systematically collected by using the LAM module for automatic annotation of late potentials. Its performance was compared with the performance of the Legacy Wavefront (WF) approach using human or semi-automatic annotation of late potentials, as performed before the introduction of the LAM module. Findings from 3D-Mapping were compared between the LAM and WF techniques. Key study goals included delivering benchmark analysis of ablation techniques and workflow variations within the EMEA region and assessing the impact of the LAM module on the diagnostic capabilities of the system for VT patients, ablation strategies, safety and procedural outcome. Results A total of 208 patients were enrolled (82% ICMP). LAM significantly enlarged the mapped late potential areas compared to WF (14.8±18.3 cm² vs. 9.5±13.3 cm², p < 0.0001) and increased late potential detection (1082 ± 1233 vs. 636 ± 1031, p=0.0010). A strong association (85%) was observed between identified late potential regions and VT circuit induced. Procedure duration averaged 2 hours 15 minutes. The overall complication rate was 8.3%, which included TIA (1.7%), Cardiac Tamponade (1.6%), Groin complications (1.7%), AV Block (1.7%), Cardiac Failure (0.8%), and Mitral Regurgitation (0.8%). Discussion While LAM has demonstrated promising results, further studies, particularly comparative studies with long term follow-up, are necessary to determine whether LAM may be superior to existing techniques for ventricular mapping during VT ablation.