First Case of Endoscopic Resection for Left Atrial Appendage Aneurysm with Suspected Viral Myocarditis: A Multimodal Approach-Uncorrected Proof.

Left atrial appendage aneurysm (LAAA) is a rare cardiovascular anomaly, with fewer than 200 documented cases. It is often associated with severe complications, such as arrhythmias and thromboembolic events. Recent evidence suggests that viral infections, particularly viral myocarditis, might be an underlying cause of LAAA. We report the case of a 36-year-old woman with a history of asthma who presented with palpitations and atrial tachyarrhythmia two months after a severe upper respiratory infection. Transthoracic echocardiography revealed a large aneurysmal left atrial appendage (LAA) measuring 5.6 × 3.5 cm and a reduced left ventricular ejection fraction of 50%. Cardiac computed tomography confirmed the LAAA and revealed abnormal flow dynamics. Late gadolinium enhancement showed mid-subepicardial hyperenhancement in the posterolateral segments of the left ventricular wall, consistent with a previous myocarditis. The patient underwent a novel, minimally invasive endoscopic thoracoscopic resection of the aneurysm, guided by transesophageal echocardiography. No thrombus was present. The procedure was successfully completed with the aid of cardiopulmonary bypass. This case highlights a potential association between viral myocarditis and LAAA, while also acknowledging the possibility of a congenital and incidentally discovered aneurysm. It underscores the critical role of multimodal imaging in accurate diagnosis and management. The successful minimally invasive surgical resection and subsequent restoration of cardiac function demonstrate the effectiveness of this approach, offering a promising outlook for patients with LAAA. Clinicians should consider viral infections as potential contributors to LAAA development and advocate for early diagnosis and intervention to improve clinical outcomes.