Detection of aortic porcine valve dysfunction by maximum entropy spectral analysis.

Foale, Rodney A.; Joo, Tae H.; McClellan, J.H.; Metzinger, R. W.; Grant, G L; Myers, Gordon S.; Lees, Robert S.

doi:10.1161/01.cir.68.1.42

Cited by 28 publications

(2 citation statements)

References 31 publications

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METHOD AND ANALYSISA surgical protocol was designed to implant, in dogs, a Medtronic AV sequen tial rate-programmable pacemaker (Model 7005C) and to destroy the AV node with one to four 0.1 ml formaldehyde inj ec tions.After a recovery period of two to three weeks, a second investigation was then set-up to record the following sig nals: the ECG, the intracardiac left ven tricular and aortic pressures, the intra cardiac left ventricular and aortic phonocardiograms (PCGs), two thoracic PCGs and the left ventricular pressure derivative. The thoracic sounds were recorded with two Hewlett-Packard contact microphones (Model 21050A).

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confidence: 99%

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A method for studying the effects of PR and RR intervals on heart sound power spectra

Durand¹,

Langlois²,

Cloutier³

et al. 1988

Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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Models of valve sound production [1][2] and cl inical studies [3][4][5][6][7][8] have demon strated that the natural modes of reso nance of biological heart valves increase with calcium deposit and stiffening of the valve leaflets.In the course of ex ploring the potential of spectral analy sis of valve closing sounds for the de tection of valvular degeneration, a method was developed for determining, in dog, the influence of PR interval (PRI) and heart rate (HR) on the spectra of intracardiac and thoracic first and sec ond heart sounds. METHOD AND ANALYSISA surgical protocol was designed to implant, in dogs, a Medtronic AV sequen tial rate-programmable pacemaker (Model 7005C) and to destroy the AV node with one to four 0.1 ml formaldehyde inj ec tions.After a recovery period of two to three weeks, a second investigation was then set-up to record the following sig nals: the ECG, the intracardiac left ven tricular and aortic pressures, the intra cardiac left ventricular and aortic phonocardiograms (PCGs), two thoracic PCGs and the left ventricular pressure derivative. The thoracic sounds were recorded with two Hewlett-Packard contact microphones (Model 21050A). The in tracardiac measurements were obtained with a Millar dual-micromanometer catheter (Model SPV 350) inserted into the left or right carotid artery and pushed toward the left ventricle until pressure tracings showed that the distal transducer was in the left ventricle and the proximal in the aorta. All PCGs were processed by third order high-pass fil ters (50 HZ). PRI and HR were then var ied independently by using a Medtronic pacemaker programmer (Model 9710) and the signals recorded on a 8-channel Fostex FM tape recorder. During playback, the recorded sig nals were digitized with 12-bit reso lution by using a Data Translation acqui sition board (Model DT-2801A) installedin an IBM-PC/ AT. A QRS detection algo ri thm was used to synchronize the cohe rent detection of the mitral and aortic valve closing sounds using a cross-corre lation technique. The individual sounds selected were corrected for their jitter and transformed in the frequency domain using a sine-cosine window and a fast Fourier transform algorithm.Estimates of the mitral and aortic closing sound power spectra were obtained by ensemble averaging over 50 cardiac cycles. RESULTS AND DISCUSSIONA typical example of the influence of PRI on the spectra of intracardiac and thoracic heart sounds is shown in Fig. 1. In this preliminary study done in one dog, four PRIs (25, 75, 125 and 175 msec.) were analyzed at a constant HR of 100 bpm. Panel A shows the results for 51 recorded within the left ventricle (S11v) and externally at the apex (Sl ao ) while panel B shows the results for 52 recorded within the aorta (52 �9 ) and ex ternally at the aortic area \62 ). It is clear that, for both intracar �ac and external recordings, the influence of the PRI is significant for Sl and relatively negligible for S2. Fig. 2 shows an example of the in fluence of HR on the spectra of the in tracardiac and thoracic S...

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“…ABSTRACT Models of valve sound production [1][2] and cl inical studies [3][4][5][6][7][8] have demon strated that the natural modes of reso nance of biological heart valves increase with calcium deposit and stiffening of the valve leaflets.…”

mentioning

confidence: 99%

A method for studying the effects of PR and RR intervals on heart sound power spectra

Durand¹,

Langlois²,

Cloutier³

et al. 1988

Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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Classification of Cardiac Tones of Mechanical and Native Mitral Valves

Dimauro

Caivano

Ciccone

et al. 2021

Lecture Notes in Electrical Engineering

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Automatic detection of sounds and murmurs in patients with lonescu-Shiley aortic bioprostheses

Baranek

Lee

Cloutier

et al. 1989

Med. Biol. Eng. Comput.

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The problems encountered in the automatic detection of cardiac sounds and murmurs are numerous. The phonocardiogram (PCG) is a complex signal produced by deterministic events such as the opening and closing of the heart valves, and by random phenomena such as blood-flow turbulence. In addition, background noise and the dependence of the PCG on the recording sites render automatic detection a difficult task. In the paper we present an iterative automatic detection algorithm based on the a priori knowledge of spectral and temporal characteristics of the first and second heart sounds, the valve opening clicks, and the systolic and diastolic murmurs. The algorithm uses estimates of the PCG envelope and noise level to identify iteratively the position and duration of the significant acoustic events contained in the PCG. The results indicate that it is particularly effective in detecting the second heart sound and the aortic component of the second heart sound in patients with Ionescu-Shiley aortic valve bioprostheses. It has also some potential for the detection of the first heart sound, the systolic murmur and the diastolic murmur.

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Detection of aortic porcine valve dysfunction by maximum entropy spectral analysis.

Abstract: A high-resolution method of spectral analysis, of the class generally called "maximum entropy method," was used in a study of aortic porcine valve closing sounds in 37 patients (

Cited by 28 publications

References 31 publications

A method for studying the effects of PR and RR intervals on heart sound power spectra

A method for studying the effects of PR and RR intervals on heart sound power spectra

Classification of Cardiac Tones of Mechanical and Native Mitral Valves

Automatic detection of sounds and murmurs in patients with lonescu-Shiley aortic bioprostheses

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