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Updated: May 13, 2026
Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System
Published on: April 11, 2025
Near-field substrate analysis in ventricular tachycardia: a novel approach to identify the critical isthmus
Federica Giordano1,2, Federico Ballacci1,2, Chiara Pavone1
1Department of Cardiovascular and Thoracic Sciences, Catholic University of the Sacred Heart, Rome, 00168, Italy.
Background:
Ablation of ventricular arrhythmias (VA) relies on accurate electroanatomical mapping (EAM) to identify critical reentry circuit sites. Analysis of local peak frequency (PF) and Vector Field Disarray (VFD) may serve as useful metrics to improve EAM accuracy.
Methods:
We retrospectively analyzed high-density EAM data from consecutive patients who underwent VT ablation using the EnSite X System with Advisor HD Grid catheter at our institution. PF and VFD distributions were analyzed for co-localization with conventional substrate markers and activation-mapped VT isthmus sites. The diagnostic accuracy of PF for identifying VT isthmus sites was assessed using mixed-effects models and ROC analysis.
Results:
Sixty maps from 34 patients (70.5 years, 52.9% ischemic) were analyzed. Within low-voltage areas, median PF was 280 Hz and VFD 60%. At baseline, VT isthmus sites had higher PF than non-isthmus sites (372 ± 96 vs. 247 ± 84 Hz, p < 0.0001), with 16% higher odds of isthmus presence per 10-Hz increase (OR 1.016, p < 0.0001, AUC 0.849). A 315 Hz threshold provided an accuracy of 78% (sensitivity 72%, specificity 84%) in identification of isthmus areas. Post-ablation PF decreased to 123 ± 42 Hz (p < 0.0001).
Conclusion:
Analysis of PF and VFD may enhance the identification of VT critical isthmus sites by improving near-field signal annotation and detecting wavefront collision zones. These metrics should be considered as a complementary tool to conventional EAM.
