One of the biggest risk factors for this condition in cats.
Untitled Document
“A dilated left atrium is one of the biggest risk factors for aortic thromboembolism. In a study of cats with hypertrophic cardiomyopathy, those with aortic thromboembolism had a significantly larger left atrial diameter than those that had congestive heart failure alone or had subclinical disease.”
-Timothy Koors, DVM, H. Cecilia Marshall, DVM, DACVIM (cardiology)
From How to handle feline aortic thromboembolism