Although data from cardiac catheterization and in vivo studies are available, phonocardiographic and ultrasonic characteristics of the Medtronic Hall valve in the mitral position have not been adequately established. Phonomechanocardiographic, echocardiographic and Doppler echocardiographic examinations were performed in 15 patients (Medtronic Hall group) with a Medtronic Hall mitral valve prosthesis to elucidate the phonocardiographic and ultrasonic characteristics of the normally functioning Medtronic Hall valve in the mitral position. These findings were compared with those obtained from 20 patients (Björk-Shiley group) with a normally functioning Björk-Shiley 60 degrees mitral valve prosthesis. Simultaneous recordings of the phonocardiogram and M-mode echocardiogram of the prosthetic valve in patients in the Medtronic Hall group revealed three opening clicks relating to disc motion. The timing of the three opening clicks correlated with the onset of disc opening, the completion of disc opening, and a notch which appeared about 30 msec after the completion of disc opening. Similar recordings performed in patients in the Björk-Shiley group revealed that the third opening click was detected in only half of the patients and that its timing was nearly twice as early as that noted in the Medtronic Hall group. The Medtronic Hall group had significantly shorter durations of the apical diastolic rumble and the slow filling wave on the apexcardiogram, as well as significantly reduced peak mitral inflow velocity during early diastole and shortened pressure half-time on the mitral inflow velocity curve. Transesophageal Doppler echocardiography demonstrated slight mitral regurgitation in all patients in both the Medtronic Hall and the Björk-Shiley groups.(ABSTRACT TRUNCATED AT 250 WORDS)