Ultrasonic Closing Click of the Prosthetic Cardiac Valve

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概要

• 論文の詳細を見る

• Mechanical prosthetic cardiac valves generate not only the widely recognized audible closing clicks but also ultrasonic closing clicks, as previously reported by us. A personal-computer-based measurement and analysis system with the bandwidth of 625kHz has been developed to clarify the characteristics of these ultrasonic closing clicks. Fifty cases in total were assessed clinically, including cases with tilting disk valves, bileaflet valves, and flat disk valves. The ultrasonic closing clicks are damped vibrations continuing for about two milliseconds, and their frequency range was confirmed to be from 8kHz to 625kHz, while that of the audible click was up to 8kHz. Although the sensitivity of the sensor decreased by approximately 30dB at 625kHz, effective power of the ultrasonic closing click was confirmed at this frequency. Moreover, it was shown that, surprisingly, the signal power at 625kHz was still at the same level as that at around 100kHz. Those wide bandwidth signal components exist independent of the type of mechanical valve, but the spectral pattern shows some dependence on the valve type.

• 一般社団法人電子情報通信学会の論文
• 1998-12-25

著者

• Kobayashi Kenji

  The Faculty Of Engineering Takushoku University

• Matsumoto Hiroshi

  The Graduate School Of Engineering The University Of Tokyo

• Hasegawa Jun

  The Faculty Of Engineering Takushoku University

関連論文

• Total Obliteration of Colonic Lumen by Localized Giant Inflammatory Polyposis in Ulcerative Colitis: Report of a Japanese Case
• Ultrasonic Closing Click of the Prosthetic Cardiac Valve

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