Left atrial appendage thrombus in a patient in sinus rhythm with endocarditis and a severe aortic valve insufficiency.

A left atrial thrombus is most often associated with atrial fibrillation and/or rheumatic mitral stenosis. It is very infrequently detected in the presence of sinus rhythm. The present report describes the case of a 66-year-old woman who presented with a stroke and was subsequently found to have two potential sources of embolization, including a vegetation on the native aortic valve, with associated severe aortic insufficiency, and a left atrial appendage thrombus despite being in sinus rhythm. To the authors' knowledge, the present report is the first to describe a left atrial thrombus in sinus rhythm associated with aortic valve endocarditis.