Fig. 4. Kaplan-Meier plot of the freedom from worsening mitral regurgitation from the 1st echocardiogram to the last follow-up echocardiogram, in 37 nonsurgical patients who had at least 2 echocardiograms. The numbers above the X axis are the numbers of patients available for follow-up at 3, 6, 9, 12, and 15 years.