Heart sounds

Question 1

What is S1 ? “lub”

Answer 1

Tricuspid and Mitral valve closing

Question 2

What is S2? “dub”

Answer 2

Pulmonary and Aortic valve closing

Question 3

When can S3 and S4 be heard ?

Answer 3

In different parts of diastole

Question 4

What is happening during S3 ?

Answer 4

• In early diastole, which is right after S2, the atrioventricular valves are open and blood is flowing from the atria into the ventricles. If there’s a lot of blood coming in, the ventricles fill up quickly, and fluid waves bounce off of the walls of the ventricles which makes them vibrate, creating a third heart sound, or S3. S3 sounds kind of like “lub-dub-ta”.
• In trained athletes and also in pregnancy this is totally normal and just means that the ventricles are handling extra blood volume.
• S3 can also be a sign of volume overload, like in congestive heart failure, where there’s too much volume coming into the ventricles.

Question 5

What is happening in S4 ?

Answer 5

• At the end of diastole, just before S1, the atria are contracting to get that last bit of blood into the ventricles. If the ventricles are stiff, meaning that they can’t easily relax, the atria will have to contract extra hard to push that blood in, creating the fourth heart sound, or S4.
• So, S4 sounds kind of like “ta-lub-dub”. Oftentimes, this stiffness is because the ventricular muscles have hypertrophied, or increased in size, in order to pump against high blood pressure in the aorta or pulmonary artery.
• In other words, S4 is typically a sign of pressure overload or severe hypertension.

Question 6

What are heart murmurs an indication of ?

Answer 6

• The result of turbulent blood flow
• Graded from 1- 6

1 is mild
6 is when you can hear the murmurs without an stephescope

Question 7

What is an innocent heart murmur ?

Answer 7

• Some children whose hearts are perfectly healthy you can hear a murmur
• This is because the walls are thin and vibrate with rushing blood
• They disappear as a child gets older and the heart walls thicken.

Question 8

What is a systolic murmur ?

Answer 8

• Can be heard between S1 and S2
• “lub-whoosh-dub”.
• This is when the aortic and pulmonary valves are normally open, and the mitral and tricuspid valves are closed.

There are four main causes
- STENOSIS - an aortic or pulmonary valve that’s not able to fully open, called stenosis,

• REGURGITATION OR INSUFFICIENCY - a tricuspid valve that’s not able to fully close, called regurgitation or insufficiency.

Question 9

Explain Aortic and Pulmonary valve stenosis

Answer 9

• The valve resists opening up for a moment before finally snapping open, and this causes a characteristic “ejection click.”
• Because the blood has to flow through a narrow opening in that first moment, we get increased turbulence, which creates a murmur. The murmur initially gets louder as more blood tries to squeeze through, and then as there’s less and less blood left in the ventricle that needs to go by, the murmur becomes more quiet again. This is described as a crescendo-decrescendo murmur.

Question 10

Explain Tricuspid and mitral valve regurgitation

Answer 10

These valves aren’t able to make a perfect seal, and that allows blood to leak back from the ventricles into the atria. This movement of blood can be heard as a holosystolic murmur, because it’s possible to hear blood flowing through the valve for the duration of systole.

Question 11

What is the most common cause of mitral valve regurgitation ?

Answer 11

Mitral valve prolapse

When the chordae tendineae and the papillary muscles are too weak to keep the valve tethered.

Blood leaks backwards