Giant Left Atrium

A 65-year-old man with a history of rheumatic heart disease and severe mitral stenosis and regurgitation underwent mitral valve replacement with a 27-mm St. Jude mechanical prosthesis (St. Jude Medical, Inc.; St. Paul, Minn). Chest radiography revealed marked prominence of the right cardiac border, a finding consistent with left atrial dilatation (Fig. 1). Two-dimensional echocardiography displayed massive left atrial enlargement (Figs. 2 and 3) with dimensions of 10.4 × 12.8 cm. The remaining chamber sizes, prosthetic mitral valve function, and left ventricular systolic function were normal.

Fig. 1 Chest radiograph in the anteroposterior view revealing marked prominence of the right cardiac border (arrowheads) consistent with left atrial enlargement.

Fig. 2 Transthoracic echocardiogram (parasternal short-axis view) of the left atrium (LA).

Fig. 3 Transthoracic echocardiogram (apical 4-chamber view), showing the disproportionate size of the left atrium (LA) compared with the left ventricle (LV) and the other cardiac chambers.

Left atrial enlargement is seen in a variety of cardiac conditions, including mitral valve disease, left ventricular failure, chronic atrial fibrillation, and left-to-right shunts such as those occurring with patent ductus arteriosus and ventricular septal defects. Giant left atria are defined as those measuring larger than 8 cm and are typically found in patients who have rheumatic mitral valve disease with severe regurgitation.