Abstract
Amyloidosis is associated with poor prognosis, and patients with cardiac involvement have especially poor outcomes. Cardiac amyloidosis leads to higher rates of atrial arrhythmia and an increased risk of intracardiac thrombus formation. However, atrial mechanical dysfunction due to protein deposition in amyloidosis may lead to thrombus formation in the absence of atrial arrhythmia. We present a 42-year-old male patient with familial transthyretin amyloidosis who suffered an embolic stroke that originated from a left atrial appendage thrombus in the absence of any documented atrial fibrillation. This case highlights atrial mechanical dysfunction in patients with cardiac amyloidosis and the need to better stratify thrombotic risk in this population with integration of echocardiographic parameters and transesophageal echocardiography.