Detection of Left Atrial Appendage (LAA) Thrombus: Comparison of Cardiac Magnetic Resonance Imaging and Transesophageal Echocardiogram

The identification of left atrial appendage (LAA) thrombus prior to cardioversion for
patients with atrial fibrillation is crucial. LAA thrombus can be a frequent cause of
cerebral stroke or peripheral embolism post cardioversion, and anticoagulation therapy is
required in these instances to prevent cerebral events and avoid embolization. To date, TEE
has been considered the clinical reference in detection of LAA thrombi with high diagnostic
accuracy. However, diagnosis and size estimation of LAA thrombi remains challenging due to
the complex anatomy of the LAA, and transesophageal echocardiography (TEE) is considered a
semi-invasive procedure. To date, there have been few comparative studies involving TEE and
cardiac magnetic resonance (CMR) imaging, and the results have been conflicting. With newer
CMR Imaging techniques now available, we hypothesize that comparable results will be
achieved in detecting LAA thrombus in subjects using a less invasive procedure.

Inclusion Criteria:

- atrial fibrillation

Exclusion Criteria:

- ICDs

- pacemakers

- intracranial clips

- intracranial stimulator devices

- insulin pumps

- intra ocular metal foreign bodies

- cochlear implants

- LAA amputation as part of CABG and/or valve surgery

- GFR < 60 mL/min