Echo- and phonocardiographic studies in patients with Lillehei-Kaster aortic valve prostheses.

Simultaneous echo- and phonocardiographic studies were performed in 17 patients with normally functioning Lillehei-Kaster (LK) tilting disc prosthesis in the aortic position. The LK aortic valve prosthesis was well recorded by echocardiography with a disc excursion of 14 to 25 mm and very fast opening and closing velocities, too rapid for quantitative assessment. On phonocardiography the opening click of the prosthesis was only rarely observed (2 out of 17 cases), while the closing sound was consistently present in all patients, occurring within 5 msec of the point of complete closure of aortic disc prosthesis by echocardiography. Systolic time intervals (STI) measured by combined echo-and phonocardiography were similar to the predicted values in 15 patients who had no evidence of residual cardiac dysfunction. In the remaining 2 patients, one or more components of the STI differed by more than 2 standard deviations from the predicted values, and in these there were associated findings to explain the discrepancies. This study illustrates the echo- and phonocardiographic features of the normally functioning LK aortic valve prosthesis. In addition, precise measurements of the isometric contraction and relaxation periods as well as standard systolic time intervals are possible with these techniques.