Post-Ablation cardiac Magnetic resonance to assess Ventricular Tachycardia recurrence (PAM-VT study)

Figures

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  Figure 1. Cardiac magnetic resonance segmentation integrating dark core. In the bottom panels, the raw images of LGE-CMR are shown. In the upper panels, the same images in posteroanterior view after post-processing by ADAS3D are visualized. In the first panel, pre-ablation LGE-CMR reveals an arrhythmogenic channel inside the scar. In the second panel, the LGE-CMR post-ablation segmentation is shown without considering the DC (red arrow) as dense fibrosis. In this case, the software will code that area as healthy tissue because of the hypointense pixel intensity, showing the persistence of the arrhythmogenic channel and therefore, considering the ablation procedure incomplete. In the third and fourth panels, the same post-ablation LGE-CMR is shown, but the DC area has been manually delineated (light blue area, red arrow). The maximum pixel intensity threshold used to define the scar core was selected to convert the manually selected hypointense DC area into hyperenhancement scar core. Last panel shows the final LGE-CMR reconstruction, where the pre-ablation arrhythmogenic channel does not appear, so ablation can now be considered successful in terms of arrhythmogenic channel abolition.

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  Figure 2. Arrhythmogenic channel visualization in the post-ablation LGE-CMR. Upper panel: three-dimensional reconstruction of pre-ablation LGE-CMR with the endocardial channel in the anterior wall (white arrow) from layer 10% to 30%. In the right panel activation map during VT with a clear figure-of-eight circuit using the channel shown in the LGE-CMR with diastolic potentials inside the channel. Bottom panel: three-dimensional reconstruction of LGE-CMR of the same patient 3 months after the ablation procedure. There is an increase in dense scarring produced by radiofrequency ablation that leads to the disappearance of the arrhythmogenic endocardial channel. After one year of follow-up, the patient was free of VT recurrence. Upper panel: left anterior oblique view of three-dimensional reconstruction of pre-ablation LGE-CMR with two arrhythmogenic epicardial channels. In the right panel, an isochronal late activation map during sinus rhythm is shown revealing the presence of two deceleration zones (black circles) that correspond to the entrances of both channels. Bottom panel: three-dimensional reconstruction of LGE-CMR in the same patient 3 months after the ablation procedure. There is an…

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  Figure 3. Channel visualization in a redo procedure. The upper panel shows LGE-CMR (before the first ablation procedure) with a clear CC in the posteroseptal scar in concordance with the DZ (white circle) in the isochronal late activation map (ILAM). Late and fragmented potentials were detected in that area (right panel). The bottom panel shows the 3-month post-ablation LGE-CMR with more homogenous scarring and disappearance of the more posterior part of the CC but a new exit in the anterior part of the scar (probably reconnection or incomplete ablation). The ILAM map shows the area of blockage in the upper part of the scar and a DZ in the new CC exit (with circle) with late potentials during RV pacing and diastolic potentials during VT.

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  Figure 4. Scar characteristics before and after ablation. Comparison of LGE-CMR scar characteristics before and after ablation. A clear decrease in channel mass and number of channels is observed with an increase in core mass and no differences in BZ mass.

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  Figure 5. Kaplan–Meier VT free survival curve according to reduction of conducting channels in post-ablation CMR and the number of post-ablation LGE-CMR channels.

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  Figure 6. Receiver operating characteristic (ROC) curve of the degree of conducting channels reduction in relation to ventricular tachycardia recurrence.