Left Atrial Appendage Closure after Transseptal Puncture in the Presence of Lipomatous Hypertrophy of the Interatrial Septum: A Challenging Case Report Successfully Managed with Miniaturized Transesophageal Echocardiography Guidance

Left atrial appendage closure (LAAC) is an established therapeutic option for stroke prevention in patients with atrial fibrillation who have contraindications to long-term anticoagulation. Lipomatous hypertrophy of the interatrial septum (LHIS) can significantly increase the complexity of transseptal access, posing a major challenge for successful device delivery. Miniaturized transesophageal echocardiography (miniTEE) has emerged as a key tool for four-dimensional (4D) real-time guidance in anatomically complex structural interventions, saving the possibility to avoid general anesthesia. We report the case of a 76-year-old female with paroxysmal atrial fibrillation who underwent percutaneous LAAC. Preprocedural multimodality imaging with cardiac computed tomography (CT) disclosed marked LHIS (41 mm × 34 mm) with partial superior vena cava compression. MiniTEE probe was used to guide the procedure: unlike standard intraprocedural TEE, the miniTEE does not require general anesthesia and is well tolerated by awake patients while providing continuous, high-resolution 4D imaging. Transseptal puncture was achieved using a Brockenbrough needle under continuous miniTEE visualization, followed by balloon dilation of the septum to allow sheath advancement. A 31-mm Watchman FLX device was successfully implanted with no periprocedural complications. Conclusion: LHIS is not an absolute contraindication to transseptal interventions. The miniTEE probe, integrated with preprocedural CT-derived anatomical mapping, represents a highly effective guidance strategy for safe LAAC in this challenging anatomical context, maintaining a minimalist procedure.