Background: Extrinsic compression of the left atrium (LA) is a rare and underrecognized condition that may result in significant hemodynamic compromise and atrial arrhythmias. The available evidence has been largely limited to isolated case reports and small case series, and clinical awareness has remained low. Methods: We performed a structured review of published case reports and case series indexed in PubMed between 2016 and 2026 describing extracardiac LA compression. A predefined and reproducible literature search strategy with explicit eligibility criteria was applied. The structured review included 22 publications reporting 23 individual cases of LA compression; in addition, two institutional cases with distinct etiologies were presented separately. Demographic characteristics, presenting symptoms, diagnostic modalities, complications, management strategies, and outcomes were synthesized descriptively. Results: The structured review identified gastroesophageal disorders, particularly hiatal hernia, as the most frequent etiology, followed by vascular, mediastinal, malignant, and musculoskeletal causes. Dyspnea was the most common presenting symptom, while hemodynamic compromise, pulmonary edema, and atrial arrhythmia represented the most frequent complications. Transthoracic echocardiography was the initial diagnostic modality in all reported cases, with computed tomography required for definitive etiological diagnosis. The two institutional cases illustrated both a common cause, hiatal hernia mimicking intracardiac mass, and a rare, aggressive malignant cause with extensive mediastinal involvement. Conclusions: Extrinsic LA compression arises from diverse extracardiac pathologies and may be clinically severe. Transthoracic echocardiography can serve as a pivotal first-line tool for early recognition and differentiation from intracardiac masses, while cross-sectional imaging is essential for etiological clarification. By integrating institutional experience with a structured synthesis of published cases, this review can provide practical insights to support timely diagnosis and management of this potentially life-threatening condition.

A Borizanova, E Kinova, S Beyti, A Goudev, Mohammad El Tahlawi; The Giant Left Atrium: When the Heart Outgrows the Chest, European Heart Journal - Case Rep