Transcatheter Electrosurgical Unification of a Fenestrated Atrial Septal Defect for Single Device Closure

To describe the use of transcatheter electrosurgical septal tendon transection to consolidate a fenestrated atrial septal defect into a single defect suitable for single-device closure.

1) Cross the anterior and posterior fenestrations with separate guiding catheters under transesophageal echocardiography guidance. 2) Establish through-and-through access under fluoroscopy by advancing a guidewire into the left atrium and capturing it with a snare. The guidewire in use is preprepared by removing insulation over a short segment and shaping this into a controlled "flying V" configuration before insertion, allowing it to function as the electrosurgical interface. 3) Apply controlled tension and deliver cut diathermy with nonionic flush to transect the septal tendon. 4) Balloon-size the unified defect and deploy a single septal occluder.

Risks include thromboembolism from inadequately incorporated tissue, incomplete capture of the divided tendon, and thermal injury to adjacent structures. Continuous transesophageal echocardiography guidance and careful case selection aim to mitigate these hazards.

Electrosurgical tendon transection can convert a fenestrated atrial septal defect into a single defect, enabling stable single-device percutaneous closure.