Cardiac Pulsed Field Ablation Lesion Durability Assessed by Polarization-Sensitive Optical Coherence Reflectometry

Figures

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  Figure 1.. Components of the PulseView system. GUI indicates graphic user interface; and PFA, pulsed field ablation.

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  Figure 2.. Change of tissue birefringence during ablation. A, Dotted white line shows the time of ablation. Birefringence loss during the first few seconds of ablation. B, Graph showing the change in tissue birefringence during ablation. C, Polynomial regression fitting with normalized birefringence. Red circle shows the 20% loss. BiR indicates birefringence; and PFA, pulsed field ablation.

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  Figure 3.. Acute changes in electrogram amplitude and tissue birefringence. Electrogram amplitude pre-pulsed field ablation (PFA) (A and D) and post-PFA (B and E). (Top) An example of acute lesion that resulted in chronic recovery and no fibrosis despite the presence of an acute voltage abatement of 95.1%. C, Tissue birefringence showed no loss post ablation. (Bottom) A similar change in electrogram amplitude with abatement of 96.1%. However, this lesion did create fibrosis. There is a loss in tissue birefringence seen in F. Note the ECG showed transient ST elevation post ablation, which is discussed in the text. OCR indicates optical coherence reflrectometry.

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  Figure 4.. Electroanatomical map of the right atrium 4 wk after ablation with chronic evaluation of lesions by dragging. A, Electroanatomical map (EAM) shows chronic isolation of the superior vena cava (SVC). The yellow dotted arrow shows the trajectory of dragging the catheter postablation to evaluate tissue birefringence. There is a clear loss of tissue birefringence in the line of ablation (area between the white dotted lines) that recovers when the catheter moves to the body of the right atrium. B, EAM shows chronic reconnection of the SVC with posterior and anterior electrical gaps. There is persistent tissue birefringence in the line of ablation (area between the white dotted lines).

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  Figure 5.. Loss of tissue birefringence for lesions displaying fibrosis or recovery. A, Box plot comparing the percentage of loss of tissue birefringence for lesions with chronic electrical gaps vs lesions with chronic fibrosis. B, The loss in tissue birefringence is depicted for each lesion with red lines, indicating that no chronic fibrosis vs black lines indicated chronic fibrosis. One can see grossly that regardless of the initial absolute value, which can vary depending on every animal and the tissue targeted for ablation, small drops in birefringence of <20% do not result in durable lesions, whereas a reduction of ≥20% results in chronic fibrosis. BiR indicates birefringence; and PFA, pulsed field ablation.

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  Figure 6.. Histology four weeks after ablation sparing vessels and surrounding structures. Masson trichrome staining was used in A through C. Hematoxylin and eosin staining was used in D and E. A, Preserved structure of a nerve within the ablated tissue. B, Preserved structure of arterioles and venules within the ablated tissue. C, Lymph node in close proximity to ablated tissue with homogeneous fibrosis. D and E, Preserved structure of the esophagus in close proximity to the ablated superior vena cava. Longitudinal section and transverse section.

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  Figure 7.. Gross pathology and histology examination of pulsed field ablation lesions. A, Gross pathology of the superior vena cava (SVC) 8 wk after ablation. B, Dashed line showing well-demarcated continuous fibrosis on the line of ablation. C, Masson trichrome stain of the area of ablation showing homogeneous replacement fibrosis in blue with preserved vessels (blue arrow) and nerves (orange arrow). D, Nonablated/healthy myocardial tissue below the line of ablation. E, Transition zone with islands of preserved cardiomyocytes surrounded by fibrosis.