TY - JOUR
T1 - Extraction of apex beat waveform from acoustic pulse wave by sound sensing system using stochastic resonance
AU - Fujita, Etsunori
AU - Horikawa, Masahiro
AU - Nobuhiro, Yoshika
AU - Maeda, Shinichiro
AU - Kojima, Shigeyuki
AU - Ogura, Yumi
AU - Murata, Kohji
AU - Kisaka, Tomohiko
AU - Taoda, Kazushi
AU - Kaneko, Shigehiko
AU - Yoshizumi, Masao
N1 - Funding Information:
We would like to pay tribute to the late Dr. Junichi Yoshikawa, who was the inspiration for this research. We would like to thank Dr. Toru Watsuji, Dr. Teruyo Kitahara and Dr. Yuji Tsujimura of Shiga University of Medical Science, and Dr. Koji Maeno of Fukui Prefectural Saiseikai Hospital for their valuable discussions. This research was supported by the Transportation Technology Development Promotion Competitive Funding Program from the Ministry of Land, Infrastructure, Transport, and Tourism and Hiroshima Prefecture Innovation Human Resources Development Funding Program. We commissioned outside evaluations from Mr. Brian Long, Mr. Takaharu Kobayakawa and Mr. Masashi Iwatani.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12
Y1 - 2021/12
N2 - With a sound sensing system using stochastic resonance (4SR), it became possible to obtain an acoustic pulse wave (APW)—a waveform created via a mixture of apex beat and heart sound. We examined 50 subjects who were healthy, with no underlying cardiovascular diseases. We could determine boundary frequency (BF) using APW and phonocardiogram signals. APW data was divided into two bands, one from 0.5 Hz to BF, and a second one from BF to 50 Hz. This permitted the extraction of cardiac apex beat (CAB) and cardiac acoustic sound (CAS), respectively. BF could be expressed by a quadratic function of heart rate, and made it possible to collect CAB and CAS in real time. According to heart rate variability analysis, the fluctuation was 1/f, which indicated an efficient cardiac movement when heart rate was 70 to 80/min. In the frequency band between 0.5 Hz and BF, CAB readings collected from the precordial region resembled apex cardiogram data. The waveforms were classified into five types. Therefore, the new 4SR sensing system can be used as a physical diagnostic tool to obtain biological pulse wave data non-invasively and repeatedly over a long period, and it shows promise for broader applications, including AI analysis.
AB - With a sound sensing system using stochastic resonance (4SR), it became possible to obtain an acoustic pulse wave (APW)—a waveform created via a mixture of apex beat and heart sound. We examined 50 subjects who were healthy, with no underlying cardiovascular diseases. We could determine boundary frequency (BF) using APW and phonocardiogram signals. APW data was divided into two bands, one from 0.5 Hz to BF, and a second one from BF to 50 Hz. This permitted the extraction of cardiac apex beat (CAB) and cardiac acoustic sound (CAS), respectively. BF could be expressed by a quadratic function of heart rate, and made it possible to collect CAB and CAS in real time. According to heart rate variability analysis, the fluctuation was 1/f, which indicated an efficient cardiac movement when heart rate was 70 to 80/min. In the frequency band between 0.5 Hz and BF, CAB readings collected from the precordial region resembled apex cardiogram data. The waveforms were classified into five types. Therefore, the new 4SR sensing system can be used as a physical diagnostic tool to obtain biological pulse wave data non-invasively and repeatedly over a long period, and it shows promise for broader applications, including AI analysis.
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U2 - 10.1038/s41598-021-92983-6
DO - 10.1038/s41598-021-92983-6
M3 - Article
C2 - 34211007
AN - SCOPUS:85109254174
SN - 2045-2322
VL - 11
JO - Scientific Reports
JF - Scientific Reports
IS - 1
M1 - 13711
ER -