The development of new modes of Doppler ultrasound technologies and new developments in the methods of signal electronic processing of the received ultrasonic spectra permit accurate assessments of velocities of intracardiac blood flow. Color-encoded, two-dimensional Doppler permits qualitative and quantitative evaluations of flow field velocity patterns and estimates of turbulence profiles. Studies performed utilizing these technologies include the following: 1) Doppler velocity/flow mapping in vivo and in vitro of clinical and preclinical prosthetic mitral valves; 2) comparison of in vivo Doppler ultrasound with in vitro Doppler ultrasound and laser Doppler anemometry; 3) in vivo determinations of velocity, flow turbulence profiles of prosthetic valves and comparisons made to in vitro observations as they relate to shear stresses, making correlations with clinical events; 4) assessments of mitral regurgitation; b) evaluation of the efficacy of mitral annuloplasty techniques; and 6) observations upon normal left ventricular diastolic velocity/flow events to better understand normal native mitral valve hemodynamic physiology.