When the left atrium becomes a monster: a case report

Background Congenital left atrium (LA) aneurysms are extremely rare entities in clinical practice and most frequently involve the atrial appendage and rarely arise from the body of LA, We report a case of giant LA aneurysm compressing heart and presenting in a very late stage. Case summary A 31-year-old male, who was diagnosed to have dextrocardia, rheumatic heart disease, and atrial fibrillation and was kept on medical treatment long time ago, presented with congestive heart failure symptoms and cardiogenic shock. Emergency transthoracic echocardiography was done revealing situs solitus with aneurysmally dilated LA pushing heart to the right side (dextro-posed heart), moderate mitral regurgitation, and severe pulmonary hypertension, however, pulmonary artery anatomy could not be properly visualized so computed tomography (CT) was preformed confirming diagnosis and revealing compressed pulmonary arterial tree by the dilated LA, unfortunately patient died before proceeding to surgical intervention. Discussion Congenital left atrial aneurysms are extremely rare anomaly and may be associated with significant morbidity. And, therefore, should be remembered as a potential anatomic cause of atrial arrhythmias or embolic phenomena, or both. The diagnosis may be easily established through non-invasive complementary techniques, such as echocardiography, CT, and cardiac magnetic resonance imaging. Symptomatic patients, those with large aneurysm or compelling indications for surgery should undergo surgical resection.