C43-39 Cardiopulmonary Crossfire: Left Atrial Enlargement Leading to Right Mainstem Bronchus Compression

Abstract Introduction Extrinsic bronchial compression due to cardiac enlargement is a rare but clinically significant cause of respiratory failure. This case highlights a rare cardiopulmonary interaction in which marked left atrial enlargement resulted in significant extrinsic compression of the right mainstem bronchus and subsequent respiratory failure. Case Presentation The patient is a 75-year-old female with a past medical history of heart failure with preserved ejection fraction, chronic atrial fibrillation not on anticoagulation due to recurrent upper gastrointestinal bleeding, end-stage renal disease on hemodialysis, diabetes mellitus, interstitial lung disease, and obstructive sleep apnea, who presented to the emergency department with complaints of shortness of breath. She was diagnosed with atrial fibrillation a year ago and was not on anticoagulation due to recurrent upper GI bleeding. She was being evaluated as an outpatient for Watchman device implantation. CTA of the left atrial appendage (LAA) showed evidence of a filling defect suggestive of LAA thrombus. The patient was scheduled for an outpatient transesophageal echocardiogram (TEE) for further evaluation. However, she was sent to the emergency department from the catheterization lab because she became hypoxic, saturating 80% on room air before the TEE could begin. In the emergency department, the patient received inhaled bronchodilators and IV steroids, with no improvement. The initial chest X-ray revealed significant volume loss on the Right hemithorax. CTA chest in ED was interpreted as no evidence of pulmonary embolism and mild bibasilar atelectasis involving the lateral segment of the right middle lobe. The patient was admitted for hypoxic and hypercapnic respiratory failure secondary to volume overload and possible pneumonia. She was placed on BiPAP, and arterial blood gas was consistent with respiratory acidosis. Pulmonology was consulted. Upon review of the CTA chest from ED, it demonstrated severe right mainstem bronchus compression by an enlarged left atrium. Repeated TEE attempts were made several times but were aborted due to the patient’s worsening respiratory status. Discussion While dyspnea in patients with heart failure and atrial fibrillation is often attributed to volume overload or parenchymal lung disease, mechanical airway compression by cardiac structures is a rare and often overlooked cause. Clinicians should maintain a high index of suspicion for structural airway compression in patients with unexplained hypoxia and enlarged cardiac chambers, particularly when imaging and pulmonary findings are incongruent. Comprehensive imaging review and multidisciplinary collaboration between cardiology, pulmonology, and radiology are crucial for accurate diagnosis and management. This abstract is funded by: None