Phonocardiogram of the ball-and-cage aortic valve prosthesis.

Abstract

The ball-and-cage aortic prosthesis consists of a silastic ball, which has a specific gravity of 1 1499 (S.G. of blood=1 050), enclosed within a metal cage (Starr and Edwards, 1961). The sounds produced by the ball during its movement about the cage are very characteristic and easily recognized, because they are of high frequency, short duration, and great amplitude. We have studied the phonocardiogram in patients whose aortic valves were replaced by ball-and-cage prostheses, in order to elucidate the mechanisms of these sounds, and to obtain information from them about the phases of the cardiac cycle. SUBJECTS AND METHODSThe subjects of this study were 40 patients whose aortic valves had been replaced, 34 with a Starr-Edwards prosthesis and 6 with a Magovem prosthesis. Every patient had at least two phonocardiograms: one before and one after operation. Some had several post-operative phonocardiograms as part of their clinical assessment and whenever their clinical or auscultatory findings changed. The recordings were made by a piezoelectric crystal microphone on a photographic recorder (New Electronic Products, Ltd.). Recordings were made using the high, medium, and low frequency bands. The electrocardiogram was used as a reference trace, and all recordings were made at a paper speed of 80 mm. pqr sec.The phonocardiograms were analysed with the aid of a pair of callipers and a hand lens and measurements were made to the nearest 5 msec.The following measurements were made. (1) Onset of QRS to first heart sound (electrical-mechanical interval). These measurements were corrected for heart rate byReceived August 18, 1966. 446 dividing them by the square root of the R-R interval (Bazett, 1920). In 15 patients, the phonocardiograms were recorded simultaneously with central aortic and pulmonary artery pressures. These were obtained through nylon tubing inserted percutaneously (Seldinger, 1953) by means of strain gauges (Statham G 23/D.B.), and the whole system had a resonant frequency of 34 c.p.s., with a uniform response up to 12 c.p.s. The delay in transmission of pressures was determined by a simple experiment (Raftery, 1965) and found to be 10 msec. This figure was subtracted from all pressure wave timings.The behaviour of the valve in a pulse duplicator was studied by means of a hydraulic system consisting of a Starr-Edwards aortic valve mounted in Perspex tubing of uniform diameter. A pulse duplicator (McMillan, 1955) was used to produce intermittent flow across the valve, simulating the heart beat. The movement of the ball was recorded on cine-film at 100 frames a second. During the film exposure, the rate of pulsation, the simulated ventricular pressure, and the peripheral resistance were varied, and the effects ofthese manceuvres on the movement of the ball were observed. RESULTSSystolic Sounds. The most striking feature of the phonocardiogram was the presence of a variable number of sounds associated with the beginning of the ejection period. In every case in this series there was at least one sound of v...

Clinical significance of multiple systolic clicks from Starr-Edwards prosthetic aortic valves.

“…Cine studies of ball valve motion with a pulse simulator have shown bouncing or vibrating of the ball (Dayem and Raftery, 1966b), resulting in the production of such clicks. In patients with Starr-Edwards prosthetic aortic valves with non-metal (silastic) poppets, 2 or 3 systolic clicks of low intensity have been recorded in contrast to the high intensity multiple ejection clicks recorded from Starr-Edwards prosthetic valves with metal poppets.…”

“…Reports by Dayem and Raftery (1966b) show that the poppet strikes the apex of the cage in early systole, and then collides randomly against the struts of the cage. There is some variability of this motion depending upon ejection velocity and heart rate.…”

Effects of Glucagon on Left Ventricular Function in Man with Controlled Heart Rate

“…The early systolic sound from the prosthesis Al is due to the ball impinging on the apex of the cage [5]. It is delayed relative to the onset of left ventricular ejection by the time necessary for the ball to travel from one end of the cage to the other, the ball travel time.…”

“…It is delayed relative to the onset of left ventricular ejection by the time necessary for the ball to travel from one end of the cage to the other, the ball travel time. The late systolic sound A2 is due to the ball returning to the ring [5] and coincides exactly with the end of left ventricular ejection. The ball travel time was easily calculated by substracting the A1-A2 interval from the left ventricular ejection time, and thus delays introduced by the recording systems were avoided.…”

Συμβολη Εις Την Μηχανογραφικην Μελετην Ασθενων Με Προσθετικην Βαλβιδα Εις Την Μιτροειδη Και Την Αορτην

“…Τό φαινόμενον τούτο παρετηρήθη εις 2 ασθενείς μας εκ τών οποίων ό εις κατέληξεν έν μέσω φαινομένων οξείας καρδιακής ανεπαρκείας και ή παθολογοανατομική έξέτασις τούτου άπέδειξεν άπόσπασιν τής προσθετικής βαλβΐδος έκ τής θέσεως της, ό δέ έτερος κατά τον χρόνον τής εξετάσεως ευρίσκετο εις βαρεΐαν καρδιακήν άνεπάρκειαν. βραχεΐαν τήν εν λόγω περίοδον ό ήχος διανοίξεως τής αορτικής βαλβΐδος δυνατόν να μήν είναι ακουστός λόγφ ελαττώσεως του όγκου παλμού 53 . Το φαινόμενον τοΰτο συμβαίνει και επί φυσιολογικής βαλβϊδος παρουσία κολπικής μαρμαρυγής, εις δέ τήν ήμετέραν έργασίαν παρετηρήθη εις 2 πε ριπτώσεις.…”