270 likes | 718 Views
Qualities of Sound. Frequency (CPS = Hz) Perceived as pitchAmplitude Perceived as loudnessHarmonics Perceived as qualityDynamics Perceived as loudness changes . Pitch
E N D
1. Auscultation-Essential and Irreplaceable Stewart L Nunn MD
University Distinguished Professor
Medicine/Cardiology
The University of Tennessee
2. Qualities of Sound Frequency (CPS = Hz) Perceived as pitch
Amplitude Perceived as loudness
Harmonics Perceived as quality
Dynamics Perceived as
loudness changes
3. Pitch (Hz) Pitch is important in auscultation
Most energy in heart sounds is low-frequency (20-150 Hz)
Most energy in murmurs is mid frequency (80-500 Hz)
The stethoscope bell gets all sounds
The diaphragm without a surround only gets sounds above ~100Hz
4. Loudness (Amplitude) Fletcher-Munson curve = at low volume, low frequencies are hard to hear and are perceived as low volume even if amplitude is high
Extremely low frequency sounds S3 and S4 are difficult to hear even at substantial amplitude
Selection of stethoscope head is critical the diaphragm filters out sound below 100Hz and gets rid of S3 and S4
5. Quality (Harmonics) Murmurs that sound smooth (blowing) have many frequencies that are all about the same amplitude (white noise)
Harsh murmurs have multiple inharmonic peaks that produce a grinding sound
Murmurs that are predominantly one frequency have a distinct pitch and are called musical
All these categories have diagnostically useful implications
6. Dynamics Chreshendo dechreshendo (AS) <>
Decreshendo (AR) >
Pansystolic, unvarying (MR)
7. Stethoscope Factors The stethoscope bell gets all sounds if pressed lightly and is tunable by pressing harder and turning it into a diaphragm
The diaphragm (without a surround) only gets sounds above ~100Hz and is not suitable for the study of low-frequency heart sounds but is ideal for murmurs which are higher-frequency
8. Bell
9. Diaphragm
10. Heart Sounds S1 is caused by closure of the mitral and tricuspid valves and is quieter in LV dysfunction
S2 is caused by closure of the aortic and pulmonic valves and the involved component is quieter when there is calcification and louder when there is hypertension
S2 normally splits with inspiration and its behavior is a rich source of information
S3 is caused by early diastolic ventricular filling
S4 is caused by presystolic atrial contraction delivering blood in to a nearly filled ventricle
19. Murmurs Murmurs are described by timing (systolic or diastolic), by dynamics (creshendo, decreshendo, pansystolic), by quality (harsh,blowing) and loudness
20. Aortic Stenosis
21. AS/AR
22. Mitral Regurgitation
23. MVP Click/Murmur
25. Recorded Sounds and Murmurs
26. Sequence of exam 1 Patient sitting
Look at neck veins for pressure and waves (a, v and y descent)
Listen for carotid bruits and radiated murmurs
Feel precordium for lifts and thrills
Listen with diaphragm for heart sounds and rhythm
Listen with diaphragm for murmurs in all locations
Listen specifically for aortic regurgitation along upper LSB with patient leaning forward and exhaled and diaphragm pressed hard
27. Sequence of Exam 2 Patient recumbant
Listen mostly with bell for normal and abnormal heart sounds
Study in a focused way S1 and S2
Listen for other sounds in systole
Listen in a focused way for S3 and S4
Listen at apex with bell and diaphragm for mitral regurgitation
Listen at apex with bell for mitral diastolic rumble in appropriate patients