Giant left atrium: a forgotten cause of cardiomegaly

Chest radiography remains the first and thus the most common form of cardiac imaging in contemporary practice. The plain chest x-ray (CXR) can reveal significant information about underlying pathology in the heart and lungs. In the case presented below, the CXR illustrated several features classical of ‘giant left atrium’, infrequently encountered in western countries due to its association with rheumatic heart disease. Two dimensional echocardiography confirmed massive left atrial (LA) dilatation, the cause of cardiomegaly on CXR. A 76-year-old man was admitted to hospital with a three day history of fever, lethargy, increasing dyspnoea and abdominal swelling. He had childhood rheumatic fever and had undergone mechanical mitral valve replacement 13 years previously. He also had known severe tricuspid regurgitation and chronic atrial fibrillation. On examination, there were no peripheral stigmata of infective endocarditis or lymphadenopathy. The venous pulse was raised to the earlobes with prominent V waves and there was a loud prosthetic first heart sound with systolic murmur and no diastolic murmurs. Inspiratory crackles at the both lung bases and abdominal swelling with shifting dullness were also noted, though there was no leg oedema.