P13. Incidentally Detected Cardiac Amyloidosis in the Left Atrial Appendage of Patients Who Underwent Hybrid Ablation for Atrial Fibrillation

Objective:
Several patients who underwent hybrid ablation (HA) and left atrial appendage (LAA) clipping for atrial fibrillation were incidentally found to have cardiac amyloidosis upon review of the left atrial appendage specimen sent for pathology. We sought to better characterize these patients and their outcomes after HA.

Methods
Patients with documented atrial fibrillation underwent HA and LAA clipping between the years of 2015 and 2024 at a single institution. LAA specimens were sent to pathology following clip application, where the tissue was then prepared, sectioned, and stained with both hematoxylin and eosin (H&E) and Congo Red. Slides were reviewed by a dedicated cardiovascular pathologist. Patient charts were reviewed for demographics, comorbidities, recurrence of atrial fibrillation after HA, cessation of anti-arrhythmic drugs (AADs) after HA, length of hospital stay, stroke, and death. Recurrence was defined as atrial fibrillation or atrial flutter > 30 seconds in duration beyond a 90-day blanking period on 24 hour or longer continuous monitoring.

Results
Of 192 patients who had a LAA specimen sent to pathology as part of a HA procedure, 13 patients were found to have cardiac amyloidosis (6.8%). Three patients (23%) were found to have transthyretin amyloidosis (ATTR) subtype while 10 patients (77%) were found to have atrial natriuretic factor (AANF) subtype. The median age was 73 (IQR 70-74) and 61% were male. 12 of the 13 patients had LVEF ≥ 45%. Of the four patients who have thus far been seen for their 1-year post operative follow-up, all four (100%) remained in normal sinus rhythm. None of the 13 patients experienced post-operative stroke, death, or the need for repeat ablation.

Conclusion
The prevalence of cardiac amyloidosis among patients with refractory atrial fibrillation may be higher previously thought. When possible, it may be prudent to routinely send LAA specimens during HA procedures to detect early cardiac amyloidosis. Further studies are needed to better understand role of CA in atrial fibrillation and how it may impact treatment strategies.

Gabe Weininger (1), Joy Aparicio Valenzuela (2), Tiffanie Yau (1), Andre Vu (2), Sabrina Sanchez (2), Terrence Pong (3), Gerald Berry (4), Anson Lee (1), (1) Stanford Department of Cardiothoracic Surgery, Stanford, CA, (2) Stanford School of Medicine, Stanford, CA, (3) Stanford Department of Cardiothoracic Surgery, Foster City, CA, (4) Stanford Department of Pathology, Stanford, CA

Gabe Weininger

Poster Presenter

Gabe Weininger is a PGY2 in the Integrated Cardiothoracic Surgery Residency Program at Stanford University. He is a member of the Y. Joseph Woo laboratory and collaborates with Dr. Anson Lee on surgical ablation research. Gabe is a graduate of Yale School of Medicine and Stanford University. In his spare time he is an avid skier.