Auscultatory and echophonocardiographic characteristics of the normally functioning Medtronic-Hall aortic valve prosthesis

We recorded auscultatory and echophonocardiographic findings in 30 patients who had a normally functioning Medtronic-Hall (M-H) tilting disc valve prosthesis in the aortic position. The opening and closing sounds were invariably audible. Echophonocardiography showed that a typical opening sound consisted of 2 or 3 sharp clicks which were related to the onset and termination of the disc opening excursion. The closing sound comprised at least 2 separate clicks which coincided with the onset and completion of the valve closure. An early systolic ejection type murmur was heard in 25 patients and a faint early diastolic murmur in 2. The disc motion could be recorded echocardiographically in 27 patients. The opening amplitude of the disc varied from 3 to 11 mm. The intervals from the Q wave and the first heart sound to the onset of valve opening measured 116 +/- 20 ms (mean +/- standard deviation) and 54 +/- 14 ms, respectively. The opening and closing velocities of the disc were also easily measurable but showed a wide patient-to-patient variation. In 5 patients, the examination was repeated after 8 to 12 months. The reproducibility was excellent for the auscultatory findings and fair for the echophonocardiographic time intervals and disc opening amplitude, but poor for the disc velocities. Familiarity with these normal findings should help clinicians to determine whether an aortic M-H valve functions normally or not.