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Characterization of the Korotkoff sounds using joint time-frequency analysis
John Allen1, Tobias Gehrke, John J O'Sullivan
1Regional Medical Physics Department, Freeman Hospital, Newcastle upon Tyne NE7 7DN, UK. john.allen@nuth.northy.nhs.uk
Physiological Measurement
|March 10, 2004
Summary
Joint time-frequency analysis (JTFA) reveals distinct acoustic features in Korotkoff sounds during blood pressure measurement. This advanced technique enhances understanding of blood pressure phases and may aid in assessing arterial stiffness.
Area of Science:
- Biomedical Engineering
- Cardiovascular Physiology
- Signal Processing
Background:
- Korotkoff sounds are crucial for auscultatory blood pressure measurement.
- Traditional Fourier methods provide limited information on sound characteristics.
- A need exists for more detailed analysis of Korotkoff sound phases.
Purpose of the Study:
- To compare acoustic features of Korotkoff sound phases using joint time-frequency analysis (JTFA).
- To identify characteristic differences between the five Korotkoff phases.
- To explore the potential of JTFA for improving blood pressure measurement and arterial stiffness assessment.
Main Methods:
- Korotkoff sounds were recorded from 25 healthy subjects using a digital recording system.
- Sounds were classified into five phases by an expert cardiologist.
- A MATLAB-based short-time Fourier transform (STFT) JTFA technique was applied for analysis.
Main Results:
- Phase III exhibited the highest overall amplitude and high-frequency energy.
- Phase II showed the greatest high-frequency component and longest duration, indicating complexity.
- Statistically significant transitions between phases were identified based on frequency, duration, and amplitude changes.
Conclusions:
- JTFA successfully differentiated characteristic acoustic features across Korotkoff phases.
- The study demonstrates JTFA's capability to provide detailed insights beyond traditional methods.
- Exploiting time-frequency characteristics may enhance blood pressure measurement accuracy and arterial stiffness evaluation.