Non-rheumatic giant left atrium: An illustrative case successfully treated by surgical intervention

A 45-year-old male presented to us with decompensated heart failure. He had been diagnosed as having atrial fibrillation when he was 31 years old. Transthoracic and transesophageal echocardiography revealed an excessive left atrial (LA) enlargement with left ventricular dysfunction and severe functional mitral regurgitation. There were no specific findings of rheumatic valve disease. He underwent surgical mitral valve replacement and LA volume reduction surgery after optimal medical therapy. Surgically-removed specimens of the LA and the anterior mitral leaflet were examined and there were no specific histopathological findings suggesting the specific etiology of the giant LA in this patient. The patient's condition significantly improved after the surgery without any cardiac events ever since.