Efficacy of Optison Echo Contrast to Detect Thrombus in Left Atrial Appendage

Accurate determination of the presence or absence of left atrial appendage (LAA) thrombus has a large impact on the clinical course of patients with atrial fibrillation or ischemic stroke and has large financial implications as well. Misdiagnosing the presence of LAA thrombus can lead to unnecessarily cancelled procedures (cardioversion and atrial fibrillation ablation) and potentially hazardous, unnecessary changes in clinical care (such as prolonged Coumadin anticoagulation). Missing LAA thrombus can result in continuation of cardioversion or atrial fibrillation ablation procedures at a time when there is higher risk of subsequent embolic stroke. Several of the patients with atrial fibrillation require transesophageal echocardiography (TEE) performed prior to cardioversion or atrial fibrillation ablation procedures. There is opportunity to enroll most of these patients in our proposed study. There has been essentially no work published about the use of echo contrast materials in TEE (other than agitated saline), particularly the use of Optison. Thus, the investigators will be exploring a new field in echocardiography and echo contrast.