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PCG
- 1. VELTECH DEPARTMENT OF ECE PhonoCardiogram-PCG PreparedBy, V.Mahalakshmi, Assistant Professor, Department of ECE, Veltech
- 2. Phonocardiogram (PCG) • Phonocardiographyis the study of different heart sounds. • The phonocardiograph is the instrument used to pick up the different heart sound, filter the required and display. • The phonocardiogram is the graphic record of heart sounds. Two categories • Heart sound- transient characteristics with short duration occurs due to opening and closing of the heart valves. • Murmurs- noisy characteristics with long duration occurs due to turbulent blood flow in heart.
- 3. PIONEERS • Hippocrates laidthe foundation for auscultation • Robert Hook realized diagnostic use of cardiac auscultation • Biggest breakthrough in auscultation: Rene Laennec invented stethoscope • Dr. Jean Bennett Maguire devised a method of real-time spectral phonocardiography for the detection and classification of heart murmurs.
- 4. Development of stethoscope Earlymonaural stethoscope Modern binaural stethoscope Modern electronic stethoscope
- 6. Classifications of heartsounds • Valve closure sound - This sound occurs at the beginning of systole and at the beginning of diastole. • Ventricular filling sound - This sound is occurred at the time of filling of the ventricles. • Valve opening sound - This sound occurs at the time of opening of atrio- ventricular valves and semi lunar valves. • Extra cardiac sound - This sound occur in mid systole or late systole or early diastole
- 7. PCG Signal Characteristics 3factors of PCG Signal • Frequency – (10 to 1000 Hz) • Amplitude • Quality
- 8. PCG Signal Characteristics •1st Heart sound: • Closure of mitral and tricuspid valves. • Frequency- 30 to 100Hz and duration 50 to 100ms. • 2nd Heart sound : • Closure of aortic and pulmonary valves. • Frequency- 30 to 100Hz and duration 25 to 50ms.
- 9. PCG Signal Characteristics •3rd heart sound: • Blood rapid movement into relaxed ventricular chambers • Frequency – 10 to 100 Hz and duration 0.04 to 0.08 S. • 4th heart sound • Atrial contraction. • Frequency 10 to 50HZ and duration 0.03 to 0.06S
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- 13. • Aortic stenosismurmur – This murmur is occurred when the blood is ejected from the left ventricle through aortic valve due to resistance to ejection, the pressure in the left ventricle increased. So turbulent blood flow occur. This turbulent blood impinging the aortic valve. So intense vibration is produced. It produces loud murmur. • Mitral regurgitation murmur- In this murmur, blood flows in backward direction through the mitral valve during systole. • Aortic regurgitation murmur – During diastole, sound is heard. In diastole blood flows in the backward direction from aorta to left ventricles when valves are damaged, then this sound is heard. • Mitral stenosis murmur – This murmur is produced when blood is passed from left atrium to left ventricle. This sound is very weak.
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- 15. TYPES OF MICROPHONESUSED IN PCG 1. Air coupled microphone- • Movement of chest is transferred through the air cushion. • It provides low mechanical impedance to the chest. 2. Contact microphone • It is directly coupled to the chest wall and provides high impedance, high sensitivity, and low noise. • It is light in weight.
- 16. Amplifier • Offer selectivehigh pass filter to allow frequency cutoff • Bandwidth : 20- 2000Hz • Amplify signal Filter • Permit selection of suitable frequency bands • Avoid aliasing • Separate louder low frequency signals from lower intensity, much informative high frequency murmurs.