Non-invasive electroanatomic mapping to reduce mapping time during catheter ablation of outflow tract ventricular premature depolarizations

Purpose: Ventricular premature depolarizations (VPD) commonly arise from the septal anterior right ventricular outflow tract (sRVOT), the left coronary cusp (LCC), and the distal great cardiac vein (dGCV), and share common ECG characteristics. To assess the diagnostic accuracy of non-invasive electroanatomic mapping (NIEAM) in differentiating VPD origin between sRVOT, LCC and dGCV and quantify its clinical utility in eliminating unnecessary mapping and ablation.

Methods: ECGs and NIEAMs (CardioInsight, Medtronic) from 32 patients (56.3 ± 15.2 years) undergoing ablation for VPDs originating from sRVOT, LCC, or dGCV were blindly reviewed for their diagnostic accuracy in predicting the SOO. A 2-step algorithm using NIEAM-based activation timing of the superior basal septum of < 22.5 ms and lateral mitral annulus of > 60.5 ms was compared with subjective ECG evaluation, the maximum deflection index (MDI), and the V₂ transitional ratio in predicting SOO. We calculated the mapping and ablation time that could have been avoided had the operators relied on activation timing by NIEAM in designing their mapping and ablation strategy.

Results: NIEAM was superior to subjective ECG evaluation, MDI, and V₂ transition ratio in predicting the SOO yielding a sensitivity and specificity of 96.9% and 98.4% respectively. Using NIEAM in determining the SOO would have obviated 22 ± 4.5 min of mapping in the wrong chamber and prevented unnecessary ablation of 4.5 ± 1.8 min.

Conclusion: NIEAM has high diagnostic accuracy in differentiating between sRVOT, LCC, and dGCV VPDs, and can significantly reduce mapping time, obviating the need for unnecessary access and ablation.