Scar conducting channel characterization to predict arrhythmogenicity during ventricular tachycardia ablation

Figure 1. LGE-CMR reconstruction of the LV with an anterolateral scar in the superior panel (A) and an anteroapical scar in the inferior panel (B). We can distinguish the core and BZ from the healthy myocardium. A line is drawn over the surface representing a conducting channel (A,B). We can see substrate evolution through different layers, from the endocardium (10–30%) to the epicardium (70–90%). LGE-CMR = late gadolinium enhancement cardiac magnetic resonance; LV = left ventricle; BZ = border zone.

Figure 2. Protectedness Panel (A) Protectedness: measure of the length of the protected part (the isthmus) of a corridor. Three examples of HTCs with high protectedness, medium protectedness and low protectedness, respectively. HTC = heterogeneous tissue channel Panel (B) Protectedness computation: HTC centerline surrounded by the area of analysis for protectedness and nearby core and/or healthy tissue The percentages of HTCs that had core tissue, healthy tissue or only border-zone tissue were analyzed within a 3.5 mm distance. Based on these percentages, the local protectedness of the point was determined: If healthy tissue was found anywhere, the local protectedness was set to zero. If no healthy tissue was found, then the percentage of the perimeter that coincided with core tissue determined the local protectedness. Having less than 15% core yielded a local protectedness of 0%, and having more than 40% yielded a local protectedness of 100% (fully protected corridor point). Core values between 15% and 40% (partially protected corridor points) were mapped linearly to local protectedness values between 0% and 100%. Finally, the local protectedness values were integrated over the whole…

Figure 3. Comparison between the EAM from the VT procedure and LGE-CMR. Panel (A) Left: Activation mapping during VT. Right: LGE-CMR reconstruction of the LV (core, BZ and healthy myocardium are represented). The entire VT cycle length and the diastolic path are located in the anterolateral region of the LV. CMR shows an anterolateral scar and three HTCs (lines). The CC used by the VT on the EAM corresponds to HTC number 2 on CMR, which has a greater BZ mass than the others (5.8 g vs. 1.1 corridor 1 and 0.6 g corridor 3). Panel (B) An example of midmyocardial VT is shown. EAM shows a focal activation pattern with the earliest activation site in the midseptum, with presystolic electrograms. LGE-CMR shows an intramural septal scar (40% layer is shown) with an HTC (line) in the same spot of the earliest activation site. EAM = electroanatomic map. VT = ventricular tachycardia. LGE-CMR = late gadolinium enhancement cardiac magnetic resonance. LV = left ventricle. BZ = border zone. CC = conducting channel. CMR = cardiac magnetic resonance. HTC: heterogenous tissue channel.)

Figure 4. Predictions of the probability of arrhythmogenicity with logistic regression for length, mass, number of ramifications and protectedness.