Is it a thrombus or a tumor? An imaging dilemma for clinicians.

Atrial fibrillation, the most common cardiac arrhythmia in the Western world, confers a 5-fold increase in stroke, mainly due to thrombus formation in the left atrial appendage. Early rhythm control is often beneficial in reducing adverse cardiovascular events in higher-risk populations. Here, we present a patient who was found to have a 1 cm stalk-like lesion in the left atrial appendage on transesophageal echocardiogram prior to electrical cardioversion. Using multiple cardiac imaging modalities, including cardiac magnetic resonance imaging and computed tomography, the mass was eventually determined to be a chronic resolving thrombus.