Canadian Journal of Cardiology
Clinical Research|Articles in Press

Utility of Substrate Mapping Using Extra-systole to Localize Comprehensive Ventricular Tachycardia Circuits - Results from Intra-Operative Mapping Studies

Published:March 12, 2023DOI:



      Substrate mapping-based identification of all ventricular tachycardia (VT) circuits (diastolic activation), including partial and complete diastolic circuits in clinical and non-clinical VT, could be beneficial in guiding VT ablation to prevent VT recurrence. The utility of extrasystole induced late potentials has not been compared to late potentials in sinus rhythm and RV pacing.


      Intraoperative simultaneous panoramic endocardial mapping of 21 VTs in 16 ischemic heart disease patients was performed using a 112-bipole endocardial balloon. The decrement of near field EGM later than surface QRS during extrasystole (eLP) was studied.


      Patients were predominantly male (75%) with a mean age of 52 ± 9 yrs. The mean sensitivity of eLP (0.75[95% CI:0.72-0.78]) to detect VT circuits was better than SR (0.33[95% CI:0.30-0.36] p<0.001) and RVp (0.36[95% CI:0.33-0.39] p<0.001) without significant differences in specificity, eLP (0.77[95% CI:0.74-0.81], SR (0.82[95% CI:0.80- 0.84] p=0.23), and RV pacing (0.81[95% CI:0.78-0.83] p=0.11). Both NPV and PPV were significantly better for eLP mapping. The mean NPV was 0.77(0.74-0.81), 0.57(0.55-0.59), and 0.58(0.55-0.61) for eLP, SR, and RVp respectively (p<0.0001). PPV was 0.75(0.72-0.78), 0.63(0.59-0.67) and 0.63(0.59-0.67) for eLP, SR, and RVp respectively (p<0.001). Overall diagnostic performance (AUC) was significantly better for eLP (0.85[95% CI:0.80-0.90] compared to SR (0.63[95% CI:0.56-0.72] p<0.001) or RVp (0.61[95% CI:0.52-0.74] p<0.001).


      Evoked late potential mapping is a better tool to detect comprehensive diastolic circuits activated during ventricular tachycardia, compared to late potential mapping in sinus rhythm or RV pacing.

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