Abstract: A method for determining the operability status of heart valves IN VIVO. Accoustical data emanating from a heart valve to be analyzed is gathered. The data are divided into time slices, and the power, energy, and frequency relations for each time slice are calculated. The energy ratio of known peak frequencies is compared between the analysis data as gathered and known energy levels for a properly operating valve. The energy ratio of known frequency bands is also compared between the analysis data as gathered and known energy levels for a properly operating valve. Valve malfunctioning is indicated by the presence of a high change in the power and/or energy ratio at the selected key frequencies and bands.