Patients had echocardiography soon after stopping dexfenfluramine or placebo, and again 1 year later. Echocardiography is a test that uses sound waves to make pictures of the heart; it is an excellent way to look at heart valves. In each patient's echocardiogram, the researchers determined whether regurgitation was present and, if so, how bad it was. Next, they determined whether regurgitation improved, worsened, or stayed the same between each patient's first and second echocardiograms.