PMC9845546_01
The 12-lead electrocardiogram of all documented ventricular tachycardia (VT) morphologies showed wide QRS complexes with a pseudo-delta wave, inferior axis, and positive concordance in precordial leads with pattern break in lead V2 (VT1-VT3), suggesting epicardial origin. During the last procedure, only VT4 was induced before ablation.
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He previously underwent 2 ablation procedures in another hospital when 3 similar VT morphologies were induced with cycle length ranging from 240 to 420 ms (Figure 1, VT 1-3). At the beginning of the procedure, VT was easily inducible (VT4, cycle length 410 ms, Figure 1) by programmed ventricular stimulation. In addition, during the VT (VT4, Figure 1), no prematurity was demonstrated here, suggesting a deep myocardial substrate.
Bipolar radiofrequency (RF) ablation setting and substrate delineation before stereotactic body radiation therapy (SBRT). A: Fluoroscopic images of catheter position during bipolar RF energy application in left anterior oblique (LAO) and right anterior oblique (RAO) projection. B: Distance between active (left ventricle) and ground catheter (great cardiac vein) in left lateral (LL) projection is depicted. C: Endocardial 3-dimensional unipolar map displaying anterobasal low-voltage zone (yellow line) that was targeted by SBRT. CS = coronary sinus; LA = left atrium; LV = left ventricle; RV = right ventricle.
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At that time, the bipolar endocardial LV map was normal, with the discrete unipolar low-voltage zone at the anterobasal LV region that was targeted by both unipolar and bipolar RF ablation between distal electrodes of 2 catheters positioned contralaterally in the LV and GCV (Figure 2A and 2B). A 25 Gy dose was applied using the Cyberknife radiosurgery system (Accuray Inc, Sunnyvale, CA) to the anterobasal LV region, which was delineated by electroanatomical mapping (Figure 2C) and co-registered with planning computed tomography scan, as described earlier. Abbott, Chicago) was advanced into the left atrium. An LV endocardial voltage map (Figure 2) was created using the 3-D mapping system CARTO 3 (Biosense Webster, Irvine) and a 3.5 mm irrigated-tip catheter (NaviStar
Retrograde coronary venous ethanol ablation. A: The coronary sinus (CS) angiogram shows 2 septal branches at the angulation between the great cardiac vein (GCV) and anterior interventricular vein (AIV). B: Micro-balloon catheter cannulation of the second septal branch with ethanol injection; mapping wire introduced in the first septal branch. C: Late potentials (LP) were recorded by mapping wire during right ventricular pacing. D: Pace mapping in the first septal branch produced similar morphology to VT4 with a long stimulus-to-QRS interval. LAO = left anterior oblique; LV = left ventricle.
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Selective angiography of the GCV and anterior interventricular vein branches was performed using an internal mammary artery guiding catheter (Figure 3A). Two septal branches were identified at the angulation between the GCV and anterior interventricular vein and mapped using a 0.014-inch guidewire (VisionWire, Biotronik, Berlin, Germany) that was connected in a unipolar configuration to an "alligator" clip with a needle inserted subcutaneously as a reference electrode (Figure 3A and 3B). Pace mapping at the first septal branch exhibited an acceptable morphological match to VT4 with a long stimulus-to-QRS interval (Figure 3D).