To the Editor:

In 2010, a 77-year-old woman presented at our hospital with shortness of breath and congestive heart failure. In 1967—43 years earlier—she had been a patient of Dr. Denton A. Cooley, who had performed commissurotomy for her mitral valve disease. The replacement valve was made of bovine pericardial tissue. In 2007, the patient had developed chronic atrial fibrillation, which was controlled with digoxin. She had no other significant comorbidities. Upon her presentation in 2010, her electrocardiogram showed atrial fibrillation, and her echocardiogram showed severe mitral regurgitation and a left ventricular ejection fraction of 0.65.

The patient underwent mitral