Detection Of Heart Sounds Research Articles

Method and apparatus for discrimination and detection of heart sounds

A method and apparatus for transposition of heart sounds to a range easily detectable by the human ear and suitable for transmission, for discrimination of low intensity or brief sounds, and for display of the heart sounds on conventional recording devices involve steps of and means for, respectively, converting the heart sounds to electrical signals having given frequency components, providing an audio frequency carrier having further frequency components, generating a transposed output representing a sum and a difference of the frequency components and the further frequency components, filtering the transposed output to remove the difference of the frequency components and further frequency components, and generating an audible representation of the heart sounds and/or displaying a visual representation thereof. As a further feature, the inventive method and apparatus provide for detection of an envelope of heart sound intensity, and provision of a visual indication of whether or not electrical signals corresponding to heart sounds are of proper signal amplitude for consistent measurement of heart sound intensity.

Algorithm for detecting the first and the second heart sounds by spectral tracking.

A detection algorithm for the first and the second heart sounds, which is one of the most important problems in an automatic diagnostic system for phonocardiograms, has been developed. It is based on the frequency-domain characteristics of heart sounds analysed by a linear-prediction method. The performance of the algorithm has been evaluated in 187 samples that contain 881 cardiac cycles including normal and abnormal subjects. The algorithm uses low frequency spectral tracking for the time series of the phonocardiogram. It can track spectral level smoothly so that it is fairly effective for the detection of heart sounds. This tracking procedure can be used in other applications such as electroencephalogram processing.

Ventricular fibrillation during carotid-sinus stimulation.

CAROTID-sinus stimulation has proved to be an invaluable diagnostic and therapeutic tool. The response of a number of arrhythmias to its application is virtually diagnostic, and in paroxysmal atrial and nodal tachycardias, its use often results in the return of normal sinus rhythm.1 It may help to confirm the clinical impression of arteriosclerotic heart disease by the decrease in anginal pain that often follows carotid-sinus massage.2 Pulmonary edema has been reported to respond to its use.3 The transient slowing of the heart rate produced by carotid-sinus stimulation simplifies detection of heart sounds and murmurs.Reports of untoward neurologic effects of . . .

Detection of Heart Sounds at the Body Surface

Techniques are described for optimizing the use of a condenser microphone for hearing or recording heart sounds at the body surface. The object is to extend the frequency range of the sounds which can be detected and to permit recording and analysis of the maximum information which can be deduced from the sounds. The techniques involve reduction of noise threshold, relief of static pressure, efficient coupling to the body surface and acoustic and electrical equalization.