Physiology (heart sounds)

Physiology (heart sounds)

1. Physiology practical 1
(Heart sounds)
By : Osama Al-Zahrani
@OSAMA_Z96

2. 1
st
heart sound
•It is produced during isometric contraction and earlier part of
ejection period.
•It resembles spoken word ‘LUB’ of "lub-dub"
Characteristics:
•It is long, soft, low pitched sound.
•Duration of this sound is 0.10 –0.17 sec
Causes:
•It mainly occurs due to sudden closure of atrioventricular valves.
First heart sound and ECG:
•It coincides with peak of ‘R’ wave of ECG

3. 2
nd
heart sound
•It produces during the onset of diastole.
•It resembles the spoken word ‘DUB’ of "lub-dub"
Characteristics:
•It is short, sharp and high pitched sound.
•Duration of this sound is 0.10 –0.14 seconds.
Causes:
•It mainly produces during sudden closure of the semilunar valves :
(aortic & pulmonary valves).
Second heart sound and ECG:
•It coincides with the ‘T’ wave of ECG.

4. 3
rd
heart sound
•It is produced during rapid filling period of the cardiac cycle.
Characteristics:
•It is short and low pitched sound.
•Duration of this sound is 0.07 –0.10 seconds.
Causes:
•It is produced due to the vibrations which set up in ventricular wall,
due to rushing of blood in to ventricles during rapid filling phase.
Third heart sound and ECG:
•It appears between ‘T’ and ‘P’ waves of ECG.

5. 4
th
heart sound
•Itisproducedduringatrialsystoleandconsideredasphysiologicheartsound.
Characteristics:
•Itisshortandlowpitchedsound.
•Durationofthesoundis0.02–0.04seconds.
Causes:
•Itoccursduetovibrationswhichsetupinatrialmusculatureduringatrialsystole.
FourthheartsoundandECG:
•Itcoincideswithintervalbetweenendof‘P’waveandonsetof‘Q’waveinECG.

6. Heart sounds & ECG
P
QS
R
T

7. Stethoscope
-Stethoscope :
Is a medical device for auscultation & measure.
-Main part of Stethoscope :
1-Diaphragm(Use for high frequency sounds).
2-Bell(Use for low frequency sounds).
3-drum.
4-Tubing.
5-Ear tips.
-Uses of Stethoscope:
Measure heart rate & heart sound
Measure respiratory rate & respiratory sound

8. Stethoscope

9. •Auscultationmeansinthispractical:theprocessoflisteningtotheheartsound.
1-Mitral or bicuspid area :
•Situated in the left 5
th
intercostal space.
•This is the area of apex beat.
•Mitral valvesound best heart near this region.
2-Tricuspid area :
•Present over xiphoid process.
•Tricuspid valve sound best heart near this region.
(1st heart sound is best heard in this areas)
Auscultation areas
Xiphoid process

10. 3-Pulmonaryarea:
•Presentovertheleft2
nd
intercostalspaceclosetothesternum.
•Semilunarvalvesoundsarebestheardnearthisregion.
4-Aorticarea:
•Situatedoverright2
nd
intercostalspaceneartothesternum.
•Semilunarvalvesoundsarebestheardnearthisregion.
(2nd heart sound is best heard in this areas)
Auscultation areas

11. Auscultation areas

12. Auscultation areas