Unexpected Right Atrial Crossing of the Sphere‐9 Catheter Despite Stable Left Atrial Sheath Position

Figures

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  FIGURE 1. Unexpected right atrial crossing of the Sphere‐9 catheter during left atrial septal mapping. (A, B) Mapping of the left atrial (LA) septum was performed with the Sphere‐9 catheter in a deflected‐back configuration using a steerable sheath. (C–H) The catheter suddenly advanced into an unexpected space with recordable voltage. This space was initially interpreted as a reconnected right superior pulmonary vein.

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  FIGURE 2. Stable left atrial sheath position during right atrial crossing of the Sphere‐9 catheter. (A) Voltage mapping using Affera showed the position of the Sphere‐9 catheter as it suddenly advanced into an unexpected space with recordable voltage. (B–D) Simple withdrawal of the catheter allowed it to re‐enter the left atrium without any obvious change in sheath position. (E–H) Corresponding fluoroscopic left anterior oblique (LAO) views for panels A–D, showing that the sheath remained within the left atrium during these catheter manipulations.

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  FIGURE 3. Repeated occurrence of right atrial crossing of the Sphere‐9 catheter. (A) Post‐ablation mapping of the left atrial (LA) septum was performed with the Sphere‐9 catheter in a deflected‐back configuration using a steerable sheath. (B, C) The catheter again suddenly advanced into an unexpected space with preserved voltage. (D) During pulsed‐field ablation (PFA) delivery, the catheter did not enter the unexpected chamber; therefore, no inadvertent PFA was applied within the right atrium. (E, F) Overlaying the LA post‐ablation map with a semi‐transparent rendering of the pre‐ablation map clearly demonstrated that the SVC had been misinterpreted as the right superior pulmonary vein. Right superior pulmonary vein (RSPV), right inferior pulmonary vein (RIPV), left superior pulmonary vein (LSPV), left inferior pulmonary vein (LIPV), superior vena cava (SVC).

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  FIGURE 4. Bench experiment assessing passage of the Sphere‐9 catheter through a hole smaller than the lattice‐tip diameter. (A–C) When the steerable sheath was positioned perpendicular to the hole and advanced toward it, the Sphere‐9 catheter passed through the 6‐mm hole with mild narrowing of the lattice tip but without marked deformation. (D, E) When the sheath was forcefully pressed against the hole at an oblique angle, the lattice tip was deformed, and the catheter could not pass through the hole. (F) When the catheter alone was advanced without sheath support, the catheter shaft bent under the applied force, preventing the lattice tip from passing through the hole.