[Echocardiographic features of the St. Jude Medical valve prosthesis (author's transl)].

The St. Jude Medical (SJM) valve is a new low-profile bileaflet prosthesis with central flow, low transvalvular gradients and low thrombogenicity. Echocardiographic features of 212 correctly functioning SJM prostheses implanted in 160 patients were studied. A SJM prosthesis echogram is unique for the presence of echoes from two hemidisks that come together when the valve opens and separate when the valves close. The movement of the two hemidisks is not always synchronous. A little asynchronism (less than 0.01 sec.) is possible as the valve begins to open. More pronounced asynchronisms are recorded in prostheses implanted in mitral position and specially when the R-R interval is longer than 1 sec. In this case partial or definitive mid-diastolic closure of the posterior hemidisk is frequent. On the contrary the anterior hemidisk always remains in maximum open position for the complete duration of the diastole. Opening and closing velocities of the valve are extremely variable. However, opening velocity, independent of where the prosthesis is implanted, is always slower than the closing one. The opening valve interval is 0.06-0.10 sec. in mitral position and 0.03-0.05 sec. in aortic position. Echocardiography is a very useful diagnostic tool for evaluating the efficiency of SJM prosthesis. Data obtained from echograms of prostheses implanted in mitral position prove that the inertia of the valve hemidisks is similar to that of natural valve leaflets.