Successful isolation of persistent left superior vena cava using very high-power, short-duration radiofrequency ablation: Case report

Figures

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  Figure 1. Left atrial angiography and box-shaped pulmonary vein isolation. (A) Right and (B) left anterior oblique views. Box-shaped pulmonary vein isolation was performed as shown in the (C) anterior and (D) posterior views.

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  Figure 2. Persistent left superior vena cava (PLSVC) mapping and ablation points. The LASSO catheter was positioned superior to the left atrial roof to monitor electrical potentials during the procedure, as shown in panels (A) and (B). After high-density mapping with the OCTARAY catheter, radiofrequency energy was delivered to the PLSVC using a very high-power, short-duration strategy. Before ablation, high-output pacing at 10 V × 5 ms was performed to assess phrenic nerve capture; however, no diaphragmatic stimulation was observed around the entire circumference. (A) Right and (B) left anterior oblique views, and (C) anterior and (D) cranial views.

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  Figure 3. Intracardiac electrogram changes in the persistent left superior vena cava (PLSVC) during radiofrequency energy delivery. (A) Preisolation potential recorded on the LASSO catheter within the PLSVC. (B) Postisolation potential recorded on the LASSO catheter within the PLSVC. (C) Potential recorded on the LASSO catheter during pacing from the distal site of the coronary sinus catheter. Circumferential ablation within the PLSVC was performed using a very high-power, short-duration strategy, which resulted in the elimination of the potentials indicated by the white arrow in panel A, as shown in panel B. Furthermore, as shown in panel C, pacing from the distal site of the coronary sinus catheter did not delay the residual potentials recorded on the LASSO catheter (black arrow), supporting the interpretation that these signals represent far-field potentials from the left atrial appendage.

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  Figure 4. Dormant exit block revealed by high-frequency stimulation in the persistent left superior vena cava (PLSVC). The dormant exit block was revealed by high-frequency stimulation (20 Hz, 20 V × 10 ms) after adenosine triphosphate administration at the 9-o’clock position of the PLSVC. As indicated by the black arrows, atrial electrograms were observed at regular intervals during sinus rhythm, suggesting that burst pacing within the PLSVC did not occur in the atrium. This indicates the formation of a more durable exit block at this site.

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  Figure 5. Anatomical relationship between the ablation sites and the left atrial appendage (LAA). The persistent left superior vena cava (PLSVC) and LAA are anatomically close. Therefore, potential effects on the LAA should be carefully considered during ablation within the PLSVC.

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  Supplemental Figure 1. Intracardiac recordings were obtained during HFS on the LAPW in SR while inducing an atrioventricular block through ATP administration following Box-PVI in cases with both complete (A) and incomplete Box-PVI (B). A: The atrial rhythm remained unchanged by the HFS, indicating an HFS (-) response. B: The atrial rhythm was influenced by the HFS, showing an HFS (+) response, which suggests dormant "exit" conduction, although non-conducted automatic firing was noted before and after the HFS.