SESSION TITLE: Thrombosis Jamboree: Rare and Unique Cases SESSION TYPE: Rapid Fire Case Reports PRESENTED ON: 10/19/2022 12:45 pm - 1:45 pm INTRODUCTION: Atrial Fibrillation is associated with an increased risk of stroke secondary to left atrial thromboembolism. Its association with venous thromboembolism from the right atria is not well established (1). We report a rare case of a patient with atrial fibrillation (AF) with concomitant pulmonary embolism (PE) and left atrial appendage (LAA) thrombus. CASE PRESENTATION: The patient is a 61-year-old female with a remote history of provoked venous thromboembolism (VTE) and essential tremor who presented with progressively worsening dyspnea and fatigue. Her blood pressure was 121/78 mm Hg, pulse was 155 beats/min, respiratory rate was 18 breaths/min, and oxygen saturation was 93% on room air. EKG showed new atrial fibrillation with a rapid ventricular rate of 130-150 beats/min. A computed tomographic scan per pulmonary embolism protocol showed multiple acute emboli within the right middle and lower lobe. RV/LV ratio was 1.0. Troponin 0.05 ng/ml and BNP was 462 pg/ml. Transthoracic echocardiogram found EF 50-55%, normal right ventricular systolic function, no wall motion abnormalities. Bilateral lower extremity dopplers were negative for DVT. The patient was started on a diltiazem drip, however, continued to remain in RVR after 48 hours. Cardioversion was planned with a transesophageal echocardiogram (TEE) however, TEE showed left atrial appendage thrombus suggestive of prolonged duration of atrial fibrillation. An agitated saline study was negative for patent foramen ovale. During her prolonged hospitalization patient was started on metoprolol and digoxin after which rate control was achieved. The patient was discharged home on anticoagulation with a plan for atrial fibrillation ablation after resolution of thrombus. DISCUSSION: The patient was found to have acute PE without any provoking cause. This could have contributed to the development of atrial fibrillation. The TEE findings including bilateral atrial enlargement and left atrial appendage thrombus suggest a longer duration of uncontrolled atrial fibrillation prior to admission, especially considering the agitated saline study was negative for an intra-atrial shunt. In essence, she had both pulmonary arterial and venous thrombus simultaneously. CONCLUSIONS: Our report suggests that management of atrial fibrillation in the setting of LAA thrombus and PE can be challenging and may require multiple AV nodal blocking agents. The significance of venous and arterial thrombi in atrial fibrillation remains unclear. Studies are needed to assess the safety and efficacy of thrombolytics and long-term outcomes in these patients. Reference #1: Friberg L, Svennberg E. A diagnosis of atrial fibrillation is not a predictor for pulmonary embolism. Thromb Res. 2020 Nov;195:238-242. doi: 10.1016/j.thromres.2020.08.019. Epub 2020 Aug 10. PMID: 32799131. DISCLOSURES: No relevant relationships by Mukul Bhattarai No relevant relationships by radhika deshpande No relevant relationships by Abhishek Kalidas Kulkarni No relevant relationships by Raj Patel No relevant relationships by Prashanth Singanallur