Prosthetic heart valves are a blessing for people with defective heart valves. One type of mechanical heart valve that was manufactured between 1979 and 1985 has been implanted in approximately 86,000 people. Between 500 and 600 of these valves are known to have failed. The failure occurs when a thin wire strut breaks free, see Figure 1. The strut has two legs that are attached to the main body of the heart valve. Typically one of the legs breaks first, leaving the other leg intact and the heart valve still functioning. This condition is called a single leg separation. A technique that analyzes the sound generated by the heart valve was developed to detect this single leg separation. Acoustic data was acquired from implanted heart valves prior to their being explanted. These signals were processed and distinguishing characteristics have been identified that correlated the condition of the heart valve strut with its acoustic signature. An automated classification algorithm was developed and trained to predict the heart valve’s condition.