Heppler, Miranda

Background: Current guidelines recommend proceeding with cardioversion, without the explicit need for preprocedural transesophageal echocardiography (TEE), in patients compliant with oral anticoagulation for at least 3 weeks. The relevance of these guidelines remains unclear in those undergoing repeat cardioversion. Case summary: A 66-year-old male with a history of atrial fibrillation (AF) and a left atrial appendage occlusion (LAAO) device, compliant with apixaban, presented with dyspnea and lightheadedness. He was cardioverted into sinus rhythm, 10 days before symptom onset, with TEE unremarkable at the time. An ECG revealed that the patient converted back into AF and a repeat cardioversion was scheduled. At the patient’s request, a TEE was obtained, revealing a new 2 cm×1 cm thrombus in the left atrium above the WATCHMAN device. Cardioversion was canceled and the patient was hospitalized for AF management. Discussion: Cardioverted patients are at risk for thrombus formation due to atrial stunning, a transitory dysfunction of the atrial appendage and atrium, which occurs immediately after cardioversion and can persist for several weeks. The likelihood of a thrombus is further propagated by individual risk factors for stroke. Conclusion: Anticoagulation does not eliminate the risk of thrombus formation in those with increased risk factors for stroke. Further studies are warranted to assess the need for routine TEE, after cardioversion, in those with stroke risk factors on anticoagulation or who have LAAO.

Introduction and Importance: Current guidelines recommend against pre-procedural transesophageal echocardiogram (TEE) prior to cardioversion in atrial fibrillation patients compliant with oral anticoagulants for at least 3 weeks. The relevance of these guidelines remain unclear in those undergoing repeat cardioversion. Case Presentation: 66-year-old male with a history of atrial fibrillation and an implanted left atrial appendage occlusion device(LAAO), compliant with apixaban, presented with dyspnea and lightheadedness. He was cardioverted into sinus rhythm 10 days prior to symptom onset with TEE unremarkable for thrombus. Vitals were remarkable for tachycardia and electrocardiogram revealed that the patient converted back into atrial fibrillation. Patient was then scheduled for cardioversion. At the patient’s request, a TEE was obtained which revealed a new thrombus in the left atrium located on his WATCHMAN device. Cardioversion was canceled and patient was admitted for coumadin initiation with lovenox bridge along with neurological monitoring due to increased stroke risk. Clinical Discussion: Restoration of sinus rhythm after cardioversion can lead to thrombus formation due to atrial stunning, a transitory dysfunction of the atrial appendage and atrium.Atrial stunning occurs immediately after cardioversion and can persist for several weeks. Time-span of preceding atrial fibrillation, presence of structural cardiovascular disease, and atrial size impact severity of atrial stunning and duration of anticoagulation needed.While anticoagulation decreases the risk of thrombus formation, it does not completely eliminate it, especially in those with increased stroke risk factors. Conclusion: Atrial fibrillation patients are susceptible to thrombus formation after cardioversion.Further studies should be done to assess the need for routine TEE after cardioversion in those with increased risk for stroke on anticoagulants or who have LAAO.