Usefulness of Intracardiac Echocardiography-Guided Endomyocardial Biopsy for Diagnosing Transthyretin Cardiac Amyloidosis During Catheter Ablation

A 73-year-old female was referred to our hospital with worsening heart failure due to atrial fibrillation (AF) (Figure A). Transthoracic echocardiography revealed a preserved left ventricular (LV) ejection fraction of 62% with mild concentric myocardial hypertrophy (Figure B, Video 1). Her history of carpal tunnel syndrome, HF with AF, myocardial hypertrophy, and elevated troponin I (28.5pg/mL) raised concerns about the possibility of cardiac amyloidosis (CA). After 99mTc-pyrophosphate scintigraphy, transthyretin cardiac amyloidosis (ATTR-CA) was strongly suspected (Figure C).