A 76-year-old man with a history of chronic mitral regurgitation presented with symptoms of progressive heart failure. The chest radiograph (Fig. 1A) showed severe cardiomegaly (arrows), with a cardiothoracic index (CTI) > 0.7. Echocardiography (Fig. 1B) demonstrated severe biatrial dilatation, severe mitral regurgitation consistent with rheumatic valve disease, and moderate aortic and tricuspi...