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Analysis of phonocardiogram

Analysis of phonocardiogram. 4th practice Medical Informatics Biomedical Signal Processing TAMUS, Zoltán Ádám zoltanadam_tamus@yahoo.com. The phonocardiogram (PCG). The most traditional biomedical signal (stethoscope)

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Analysis of phonocardiogram

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  1. Analysis of phonocardiogram 4thpractice Medical InformaticsBiomedical Signal Processing TAMUS, Zoltán Ádám zoltanadam_tamus@yahoo.com

  2. The phonocardiogram (PCG) The most traditional biomedical signal (stethoscope) The PCG is generated by the contractile activity of the cardiohemic system (the heart and blood together) Recording: microphones, pressure transducers or accelerometers placed on the chest surface

  3. The phonocardiogram (PCG) Auscultation areas for heart sound

  4. The genesis of heart sound The heart sound are NOT caused by valve leaflets movements Vibrations of the whole cardiovascular system As the fluid filled balloon when stimulated any location

  5. The genesis of heart sound • Normal cardiac cycle contains two major sounds • the first heart sound (S1) and the second heart sound (S2)

  6. The genesis of heart sound S1 occurs at the onset of the ventricular contraction (systole)

  7. The genesis of heart sound S2 occurs at the closure of the semilunar valves (diastole)

  8. The first heart sound • The first vibration: • contractions in the ventricles • blood move toward the atria • sealing the atrio-ventricular (AV-mitral and tricuspid) valves

  9. The first heart sound • The second component: • abrupt tension of the closed AV valves • decelerating the blood

  10. The first heart sound • The third component: • the semilunar valves (aortic and pulmonary) open • the blood is ejected out of the ventricles • oscillation of blood between the root of the aorta and the ventricular walls

  11. The first heart sound • The forth component: • Turbulence in the ejected blood flowing rapidly through the ascending aorta and the pulmonary artery

  12. The second heart sound • The S2 is caused by the closure of the semilunar valves • Vibrations in the arteries due to the deceleration of blood • Ventricles and atria also vibrate due to the transmission of vibrations through blood, valves and the valve rings

  13. The second heart sound • S2 has two components • First: closure of the aortic valve (A2) • Second:closure of the pulmonary valve (P2) • A2 precedes P2 by few miliseconds • Phatologic conditions could cause this gap widen or may also reverse the order of A2 and P2

  14. The third heart sound • In some cases may be heard • sudden termination of the ventricular rapid filling phase • Low frequency: ventricles filled blood and their walls are relaxed

  15. Heart murmurs The intervals between S1 and S2, and S2 and S1 are normally silent Murmurs are caused by certain cardiovascular defects and diseases Murmurs are high frequency, noise-like sounds Turbulence in blood flow

  16. Reference Rangaraj M. Rangayyan: Biomedical Signal Analysis, IEEE Press/Wiley, New York, NY, 2002.

  17. Exercises • 1. Analysis of the heart sound • Observation of the parts of heart sound • Parts of S1 and S2 • Determination of the heart rate (pulse) • 2. Examination of heart sound in frequency domain • 3. Examination of murmurs in time and frequency domain sample files: http://zoltanadam.fw.hu software: Audacity http://audacity.sourceforge.net/

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