Authors:
Shinichi Sato
1
;
Takashi Koyama
1
;
Kyoichi Ono
1
;
Gen Igarashi
1
;
Hiroyuki Watanabe
1
;
Hiroshi Ito
1
and
Mikio Muraoka
2
Affiliations:
1
Akita University Graduate School of Medicine, Japan
;
2
Akita University Graduate School of Engineering and Resource Science, Japan
Keyword(s):
Piezoelectric transducer (PZT) sensor, Heart sound, Super low frequency sound, Cardiac diagnosis, Phonocardiographic diagnosis.
Related
Ontology
Subjects/Areas/Topics:
Biomedical Engineering
;
Biomedical Equipment
;
Biomedical Instruments and Devices
;
Biomedical Sensors
;
Devices
;
Electrocardiography and Heart Monitoring
;
Health Monitoring Devices
;
Human-Computer Interaction
;
Physiological Computing Systems
Abstract:
A variety of diagnosis that auscultation enables is not necessarily conducted thoroughly by all of the physicians because of its difficulty in judging by means of listening to evanescent sounds with their ears. A system that displays heart sounds continuously on a computer screen may be convenient for cardiac diagnosis. Recently, we made a monitor system with employing a piezoelectric transducer (PZT) sensor, which detected 1st and 2nd sound and murmurs clearly. In addition, the sensor was capable of detecting inaudible low-frequency sounds of below ~20Hz. Using the PZT sensor, we recorded heart sounds at left second intercostals space in 12 patients susceptible to cardiac diseases in parallel with ECG recording, and analysed the raw heart sounds and band-pass (20–100 Hz) filtered signal. Second sound in the filtered signal was completely or often absent and/or a sharp deflection, which appears coincidently with R wave, with a peak-peak voltage of >20 mV and a duration of <25 ms was
missing in the raw sound signal in 90% (9/10) of the patients diagnosed as having cardiac dysfunctions. Thus, we believe that the PZT-based heart sound monitor system may contribute to the advance of the phonocardiographic diagnosis of cardiac diseases.
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