Novel “late potential map” algorithm: Abnormal potentials and scar channels detection for ventricular tachycardia ablation

Abstract

Background: Automated systems for substrate mapping in the context of ventricular tachycardia (VT) ablation may annotate far-field rather than near-field signals, rendering the resulting maps hard to interpret. Additionally, quantitative assessment of local conduction velocity (LCV) remains an unmet need in clinical practice. We evaluate whether a new late potential map (LPM) algorithm can provide an automatic and reliable annotation and localized bipolar voltage measurement of ventricular electrograms (EGMs) and if LCV analysis allows recognizing intrascar conduction corridors acting as VT isthmuses.Methods: In 16 patients referred for scar-related VT ablation, 8 VT activation maps and 29 high-resolution substrate maps from different activation wavefronts were obtained. In offline analysis, the LPM algorithm was compared to manually annotated substrate maps. Locations of the VT isthmuses were compared with the corresponding substrate maps in regard to LCV. Results:The LPM algorithm had an overall/local abnormal ventricular activity (LAVA) annotation accuracy of 94.5%/81.1%, which compares to 83.7%/23.9% for the previous wavefront algorithm. The resultant maps presented a spatial concordance of 88.1% in delineating regions displaying LAVA. LAVA median localized bipolar voltage was 0.22 mV, but voltage amplitude assessment had modest accuracy in distinguishing LAVA from other abnormal EGMs (area under the curve: 0.676; p < .001). LCV analysis in high-density substrate maps identified a median of two intrascar conduction corridors per patient (interquartile range: 2-3), including the one acting as VT isthmus in all cases. Conclusion:The new LPM algorithm and LCV analysis may enhance substrate characterization in scar-related VT.

Impact of different activation wavefronts on ischemic myocardial scar electrophysiological properties during high‐density ventricular tachycardia mapping and ablation

“…The identification of the ISCC was purely based on the analysis of LCV vectors, using simple criteria recently proposed by our group. 12 Additionally, we used for the first time a novel propagation display of the LCV data superimposed on the activation maps, as shown in Supplementary Movie 1, which made the delineation of ISCC much easier. In the current study, we found that 66% of ISCCs were similarly identified in all available activating wavefronts per patient.…”

“…Maps were analyzed retrospectively using a noncommercial version of Carto®3 V8. The substrate map was analyzed using a new late potential map (LPM) software, which includes: a LAVA annotation algorithm; a localized bipolar voltage assessment; and an algorithm for automatic regional vector analysis, allowing to determine the directionality of the electrical wavefront and to display a quantitative assessment of LCV 12 —Supporting Information. Of note, localized bipolar voltage assessment allows automatic and dynamic adjustment of the window of interest focusing on the near‐field signal and excluding any far‐field component from the measurement.…”

“…LCV analysis was performed using a velocity cut‐off of 0.20 mm/ms and a compression level of 2. Intra‐scar conduction corridors (ISCC) were defined as corridors of LCV vectors with: (1) LCV ≤0.20 mm/ms; (2) localized bipolar voltage <1.50 mV; (3) length ≥10 mm; and (4) vector orientation parallel to the length of the corridor 12 —Figure 1. A novel propagation display of the LCV data superimposed on the activation maps was used to facilitate the delineation of the ISCC—Supplementary Movie .…”

Multiple wavefront substrate mapping using a novel late potential mapping algorithm: Can one wavefront rule them all?

“…Anter et al 7 have reported a different method, whereby multicomponent electrograms (EGMs) were annotated according to their spatiotemporal properties. Recently, Cortez‐Dias et al 8 have reported a novel “late potential map” (LPM) algorithm, which both automatically detects local abnormal ventricular activity (LAVA) and displays local conduction velocity (LCV). Whilst this is not currently available for independent assessment, it promises to be part of future versions of the CARTO 3 mapping system (Biosense Webster Inc.).…”

“…In this issue of The Journal, Lima da Silva et al 8 performed retrospective offline analysis of the VT substrate using this new LPM algorithm (REF). They included 16 patients with longstanding ischaemic cardiomyopathy; 3 were mapped in 3 different wavefronts, 9 in 2 wavefronts, and 4 in only 1 wavefront.…”