1. Heart Valves and Heart Sounds
Prof.Dr. Ümmühan İşoğlu-Alkaç
İ.Ü. İstanbul Tıp Fakültesi
Fizyoloji Anabilim Dalı
YU Medical Faculty,

2. Heart Valves and Heart Sounds

3. Heart Valves
Heart valves ensure unidirectional blood flow through the heart
Atrioventricular (AV) valves lie between the atria and the ventricles
AV valves prevent backflow into the atria when ventricles contract
Chordae tendineae anchor AV valves to papillary muscles

4. Heart Valves

5. Atrioventricular Valve Function

6. Heart Valves
Aortic semilunar valve lies between the left ventricle and the aorta
Pulmonary semilunar valve lies between the right ventricle and pulmonary trunk
Semilunar valves prevent backflow of blood into the ventricles

7. Heart Valves

8. Semilunar Valve Function

11. Normal Heart Sounds Closing of the valves causes audible sounds
No audible sounds occur when the valves open
“Lub” is associated with closure of AV valves at the beginning of the systole and
“Dub” is associated with closure of semilunar valves at the end of systole
The lub sound is called the first heart sound
The dub sound is called the second heart sound

12. Causes of the First and Second Sounds
First heart sound: Vibration of taut valves immediately after closure, vibration of the adjacent heart walls and major vessels around the heart
Auscultation of heart sounds by stethescope
Second heart sound: when the semilunar valves close, they bulge backward toward the ventricles
The vibration occurring in the arterial walls are then transmitted mainly along the arteries

13. Duration and Pitch of the Heart Sounds
Duration of the first heart sound is about 0.14 second
Second heart sound lasts about 0.11 second
A-V valves vibrate a little longer
The second heart sound has a higher frequency because of two factors:
Tautness of the semilunar valves in comparison with much less taut A-V valves
The greater elastic coefficient of the taut arterial walls that provide the principal vibrating chambers for the second sound

14. Third and Fourth Heart Sounds
Third Heart Sound: occasionally a third rumbling heart sound is heard at the beginning of the middle third of diastole
This is caused by oscillation of blood back and forth between the walls of ventricles
Atrial Heart sound (the fourth sound): An atrial heart sound can sometimes be heard in the phonocardiogram
It can almost never be heard with stethescope
This sound occurs when the atria contract

15. Chest Surface Areas for Auscultation

16. Two audible heart sounds: They are termed the first (S1) and second (S2).
They sound like “lub dup”.
The first is low pitched and the second is high.
Sounds come from turbulent flow around the valve cusps and vibration of the heart structures

17. Two more sub-audible heart sounds are present, the third (S3) and fourth (S4) heart sounds.

18. Too faint to be heard but can be seen in a phonocardiogram
If S3 or S4 are audible it is called a gallop.

19. S3 results from rapid filling of the ventricle during diastole.
It is sometimes heard in normal children and in some patients with heart failure

20. S4 (the atrial sound) is due to atrial systole

21. Rheumatic Valvular Lesions
The greatest number of valvular lesions result from rheumatic fever
It is an autoimmune disease, usually initiated by streptococcal toxin
Heart valves are likely to be damaged or destroyed
Lesions become scar tissue, fusing the portions of adjacent valve leaflets.
Stenosis: valve leaflets adhere to one another that blood cannot flow thorugh it normally
Regurgitation: when the valve edges are so destroyed by scar tissue that they cannot close during ventricular contraction
Stenosis usually coexists with some regurgitation or vice versa

22. Heart Murmurs Caused by Valvular Lesions
Abnormal heart sounds are known as murmurs
Systolic murmur of aortic stenosis
Nozzle effect and
Severe turbulence of blood in the root of aorta
Diastolic murmur of aortic regurtigation
No abnormal sound is heard during systole, but diastole
Turbulence of blood jetting backward into the low-pressure diastolic left ventricle

23. Heart Murmurs Caused by Valvular Lesions
Systolic murmur of mitral regurgitation
Blood flows backward thorugh the mitral valve into the left atrium during systole
Causes high-frequency sound
Occurs during systole
Felt strongly at the left atrium (apex of the heart)
Diastolic murmur of mitral stenosis
Stenosed mitral valve
Abnormal sounds heard in mitral stenosis are weak
Pressure in the left atrium rarely rises above 30 mmHg

24. Abnormal Circulatory Dynamics in Valvular Heart Disease
In aortic stenosis, contracting left ventricle fails to empty adequately
In aortic regurgitation, blood flows backward into the ventricle
In either case, stroke volume is reduced
Hypertrophy of the left ventricle:
In both aortic stenosis and regurgigation, left ventricular musculature hypertrophies because of increased workload
Increase in blood volume:
An initial slight decrease in arterial pressure
Peripheral circulatory reflexes – decreased renal output

25. Abnormal Circulatory Dynamics in Congenital Heart Disease
There are three major types of congenital anomalies of the heart and its associated vessels:
Stenosis
Congenital aortic valve stenosis
Aort coarctation
Left to right shunt (patent ductus arteriosus)
Right to left shunt (teratology of fallot)

26. Patent Ductus Arteriosus
Pulmonary artery blood flows through a special artery (called ductus arteriosus) present in the fetus that connects pulmonary artery with the aorta
This allows recirculation of blood through the systemic arteries of fetus without the blood going through the lungs
Closure of the ductus arteriosus after birth
Incidence is about 1 in 5500 births
Dynamics of the circulation with a persistent patent ductus

27. Patent Ductus Arteriosus
Symptoms become severe until the child grows older
Heart sounds: machinery murmur
A blowing murmur is heard in the pulmonary artery area of chest
Surgical treatment of patent ductus arteriosus

28. Patent Ductus Arteriosus

29. Teratology of Fallot (a right to left shunt)
It is the most common cause of “blue baby”
Most of the blood bypasses the lungs, so aortic blood is mainly unoxygenated venous blood
Aorta originates from the right ventricle rather than the left, receiving blood from both ventricles
Pulmonary artery is stenosed
Blood from the LV flows either through a ventricular septal hole into the RV or directly into the aorta
Right ventricular hyperthrophy
Abnormal circulatory dynamics: about 75% of blood is unoxygenated (venous blood)

30. Teratology of Fallot (a right to left shunt)
Diagnosis
Baby’s skin is cyanotic (blue), Measurement of high blood pressure in the right ventricle
Radiological findings (enlarged RV), Angiograms
Surgical treatment of pulmonary stenosis and closure of septal defect

31. Phonocardiogram