Study on the process of cardiomyocyte apoptosis after pulsed field ablation

Figures

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  Figure 1. PFA system, (A) the ablation catheter, (B) the electrode part at the end of the ablation catheter, (C) the schematic diagram of the catheter placed in the left atrium model, and (D) the PFA pulse generator.

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  Figure 2. The DSA image and electroanatomical mapping (image from dog B2) is presented in three parts. Part (A) shows a DSA of the PV with the yellow dashed frame marking the PV ostium. Part (B) shows the PFA ablation catheter in preparation for discharge at the right superior PV antrum, with the blue dashed box showing the developing image of PFA ablation catheter under DSA. Part (C) shows that the left atrial electroanatomical modeling before ablation reveals an unisolated state of the PV. The red dashed box portion represents the pre-ablation PV electrogram, indicating that PV signals can be transmitted.

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  Figure 3. Procedure process.

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  Figure 4. The electroanatomical mapping results immediately after surgery (image from dog B2) showed that the left atrial voltage mapping revealed low voltage in the right superior PV (RSPV). The red line frame represents the PV electrical signal after ablation, and the absence of far-field potential from the left atrium in PV indicates successful afferent block.

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  Figure 5. The remapping results (from dog A5) of the voltage maps are presented in anterior-posterior view (left side of each map) and left-anterior oblique view (right side of each map). Map A shows the preoperative left atrial modeling, Map B shows the voltage map immediately after ablation, Map C shows the voltage map 30 min after ablation, and Map D shows the voltage map 2 h after ablation. The blue wireframe in the figure represents the ablation site (left superior PV). The yellow frame in Map A partially represents the left inferior PV and its branches, and preoperative mapping revealed low voltage due to the animal itself.

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  Figure 6. (results from dogB2, ablation site: right superior PV). The two maps have different color schemes due to the different systems used. The orientation and size of the pictures have been slightly adjusted for improved viewing, but the relative position and size remain unchanged. Map A displays the mapping results immediately after surgery, with the non-blue parts representing low voltage regions. Map B displays the mapping results 30 days after surgery, with the non-purple parts indicating low voltage regions.

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  Figure 7. He staining results (observed under 40X microscope).The blue dashed line indicates the boundary between the endomyocardial intima and myocardial cells, with "a" marking the endomyocardial region, "b" marking the myocardial cell region, and "c" marking the epicardial region. The endomyocardial region in both the Day0 and control groups is small and difficult to distinguish under 40X magnification. The black wireframe region in the Day0 figure was observed under 200X magnification, while the black wireframe region in the control group was viewed under 400X magnification. The junction between the endomyocardial intima and myocardial cells is highlighted with a blue dashed line.

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  Figure 8. He staining results (observed under 400X microscope) The black dotted line marks the boundary between myocardial intima and myocardial cells. a indicates the intima layer, and b indicates the myocardial layer.

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  Figure 9. Tunel staining results (observed under 40x microscope): Tunel staining will darken apoptotic cells to brown or reddish brown, while ordinary cells will be blue or light; The black wireframe is dark apoptotic area, and Day3 and Day0 (a small amount) and Day3 have dark areas.

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  Figure 10. Schematic diagram of the ablation area after ablation.a indicates the endocardial membrane closing to the ablation electrode, which is the ablation central ablation area, and the myocardial cells in this area die instantly. b indicates the cardiomyocytes closing to the epicardium, which is the edge of ablation area, normal ablation also causes immediate death. However in some patients, this area that doesn't die immediately undergoes gradual apoptosis. c indicates the pulmonary vein. Figure A represents the normal schematic diagram after PFA, the PV electrical signal is blocked. Figure B represents the schematic diagram of AF recurrence after PFA, as the direct death area doesn't cover the epicardium due to improper operation or the patient's own condition during the operation, the situation shown in Figure B will occur, and the PV electrial signal is not isolated, as well as AF will recur. In general, normal patients will directly go through stage A after PFA, while AF recurrence patients will exprience stage B first and then type A.