Peak frequency–guided tissue proximity assessment during posterior wall isolation using the fixed-loop pulsed field ablation catheter

Figures

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  Figure 1. A case of incomplete isolation of floor area with low peak frequencies (<200 Hz) (case 1). A: Pre-PFA application peak frequency map. B: Post-PFA application voltage map. C: Preprocedural left atrial computed tomography image. Pre-PFA application peak frequency map showed high peak frequencies (>200 Hz, white color) in the anterior antrum of pulmonary veins and roof areas (A). Conversely, the floor area exhibited low peak frequencies, with an oblique line of high peak frequencies in the posterior wall. Subsequent high-density voltage mapping revealed successful electrical isolation of the roof area but incomplete isolation of the floor area (B). Furthermore, the voltage map showed an oblique, low-voltage area in the posterior wall. AP = anteroposterior; CS = coronary sinus; PA = posteroanterior; PFA = pulsed field ablation.

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  Figure 2. Additional PFA application to the floor area in case 1. A: Pre-PFA application peak frequency map of the additional application. B: Final voltage map. An additional PFA application was performed solely on the floor area. Subsequently, the pre-PFA application peak frequency in the floor area showed high peak frequencies (>200 Hz, white color) (A). The subsequent high-density map demonstrated complete isolation of the posterior wall. AP = anteroposterior; CS = coronary sinus; PA = posteroanterior; PFA = pulsed field ablation.

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  Figure 3. A case of incomplete isolation of the roof area with low peak frequencies (<200 Hz) (case 2). A: Pre-PFA application peak frequency map. B: Post-PFA application voltage map. C: Preprocedural left atrial computed tomography image. Before PFA application, the pre-PFA application peak frequency map showed high peak frequencies (>200 Hz, white color) in the floor area. However, the roof area, specifically the right side, exhibited low peak frequencies. Subsequent high-density voltage map revealed segmental incomplete isolation of the roof area (B). Red tag, application point of PV antrum; blue tag, application point of distal PV; green tag, application point of roof and floor area. AP = anteroposterior; CS = coronary sinus; PA = posteroanterior; PFA = pulsed field ablation; RA = right atrium; SEP = septal; SUP = superior; TV = tricuspid valve.

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  Figure 4. Additional PFA application to the roof area in case 2. A: Pre-PFA application peak frequency map of the additional application. B: Final voltage map. An additional PFA application was performed solely on the roof area (A). The subsequent high-density map demonstrated complete isolation of the posterior wall. Red tag, application point of pulmonary vein antrum; blue tag, application point of distal pulmonary vein; green tag, application point of roof and floor area; yellow tag, additional application. AP = anteroposterior; CS = coronary sinus; PA = posteroanterior; PFA = pulsed field ablation; RA = right atrium; SEP = septal; SUP = superior; TV = tricuspid valve.

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  Figure 5. High-density maps in the second session of case 2 for recurrent atrial tachycardia. A: Pre-PFA application peak frequency map of the first application in the first session. B: Pre-PFA application peak frequency map of additional application in the first session. C: Voltage map in the second session at 8 months after the first session. D: LAT map under CSd pacing. High-density map in the second session revealed reconduction at the anterosuperior part of the right pulmonary vein (PV) and the posterior wall (A). The LAT map showed conduction into the anterosuperior right PV, accompanied by a conduction block line in the anterior antrum of the right PV (C). The site of this block line corresponded to an area with relatively high peak frequencies (>200 Hz, white color) in the pre-PFA application map in the first session, although the superior part of the right PV had relatively lower frequencies (<200 Hz). Furthermore, a conduction block line was observed in the central posterior wall at the second session (C). This location seems to correspond to an area with relatively high peak frequencies (>200 Hz) on the pre-PFA application maps in the first session (A, B). Red tag, application…

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  Figure 6. A case of complete isolation of the posterior wall by PFA application referring to high peak frequencies (>200 Hz) sites (case 3). A: Preprocedural left atrial computed tomography image. B: Pre-PFA application peak frequency map. C: Post-PFA application voltage map. Pre-PFA application map showed continuously high peak frequencies (>200 Hz, white color) in both the roof and floor areas (B). As a result, the high-density voltage map revealed a clear PWI line consistent with the application tag (C). Red tag, application point of pulmonary vein antrum; blue tag, application point of distal pulmonary vein; green tag, application point of roof and floor area; orange circle, additional PFA applications. AP = anteroposterior; CS = coronary sinus; PA = posteroanterior; PFA = pulsed field ablation; RA = right atrium; SEP = septal; SUP = superior; TV = tricuspid valve.