S1 heart sound = beginning of Systole = mitral and tricuspids close (mitral closes before the tricuspid b/c higher pressures)
S2 heart sound = beginning of Diastole = pulmonic and aortic close (variation with respiration – as diaphragm goes down they increase the intrathoracic pressure.
Blood is being sucked into the right side of the heart, and the pulmonic valve will close later than the aortic valve. So, the second heart sound has a variation with inspiration – the P2 separates away from A2 b/c more blood coming into the right heart, so the valve closes a little bit later.
S3 heart sound = normal under 35 y/o’s. After that, it is pathologic. S1 = beginning of systole and S2 = beginning of diastole; obviously, S3 = early diastole. S3 is due to blood, in early diastole, going into a chamber that is volume overloaded. So, blood from the left atrium is going into overloaded chamber, causing turbulence, which is the S3 heart sound. Only hear S3 heart sound in volume overloaded chamber. It could be from LHF (left ventricle overloaded) or RHF (right vent overloaded), so there are left sided S3’s and right sided S3’s – it means volume overload in the chamber. Analogy: rivers going into ocean – leads to turbulence (ocean is the ventricle with a lot of 5luid in it and the river is the blood coming in
during diastole; the river hits this large mass of 5luid in the ventricle, causing turbulence and an S3 heart sound).
S4 heart sound = late diastole – this is when the atrium is contracting and you get the last bit of blood out of the atrium into the ventricles, leading to S4 sound. S4’s occur if there is a problem with compliance. Compliance is a 5illing term.
So, when talking about compliance, referring it’s ability to 5ill the ventricle. The left atrium is contracting, trying to get blood into a thick ventricle; the ventricle is noncompliant, and therefore resistance will occur. This will create a vibration, leading to an S4 heart sound. An S4 heart sound is due to a problem with compliance. The left atrium is encountering a problem in putting blood in late diastole into the left ventricle and it doesn’t want to 5ill up anymore. This could be due to 2 reasons: (1) b/c it’s hypertrophied (it doesn’t want to 5ill anymore–
restricting 5illing up) or (2) it’s already 5illed up and has to put more blood in an already over5illed chamber.
Summary: Slides:
Vol overloaded? No S3. So can it have an S4? Yes.
If you have HTN, which type of heart will you have? Concentric HPY. So, in HTN, which type of heart sound will you have? S4.
Vol overloaded? Yes. So can it have an S3? Yes; can it also have an S4? Yes. Why can it also have an S4? B/c it can’t 5ill up anymore. Analogy: turkey dinner – all 5illed up, but always room for desert – lil vibration that occurs when it 5ills is an S4 heart sound. So you have both S3 and S4 heart sound = gallop rhythm (they have S1, 2, 3, and 4).
How do you know if its from the left or right? It is breathing. When you breath in, you are sucking blood to the right side of the heart. All right sided heart murmurs and abnormal heart sounds (ie S3, S4) increase in intensity on inspiration – this is more obvious b/c there is more blood in there, and it emphasizes those abnormal sounds. Prob get them on expiration with positive intrathoracic pressures that are helping the left ventricle push blood out of the heart – this is when abnormal heart sounds and abnormal murmurs will increase in intensity on expiration. So, all you have to do is 5igure out that there is an S3 heart sound. *****Then, you have to 5igure out which side it is coming from. Louder on expiration, therefore its from the right side.
Example: essential HTN = left;
Mitral regurg = right;
and Mitral stenosis = middle.
III. Murmurs
Stenosis = prob in opening, that is when the valve is opening, and that is when the murmur occurs.
Regurgitation = prob in closing the valve, that is when the valve is closing, and that is when the murmur occurs.
Need to know where valves are heard best – right 2nd ICS (aortic valve), left 2nd ICS (pulmonic), left parasternal border (tricuspid), apex (mitral) – this isn’t necessarily where the valve is, but where the noise is heard the best.
A. Stenosis:
1. Systolic Murmurs:
Who is opening in systole = aortic and pulmonic valves = therefore, murmurs of aortic stenosis and pulmonic stenosis are occurring in systole. This is when they are opening; they have to push the blood through a narrow stenotic valve.
a. Aortic Stenosis – LV contracts and it is encountering resistance -‐ intensity of the murmur goes up; as it is pushing and pushing, it gets to a peak and this is diamond shape con5iguration – this is why it is called an ejection murmur. So, they often have diagrams of the con5igurations on these murmurs. With an ejection murmur (aortic stenosis), it will have a crescendo-‐decrescendo (hence, diamond shaped con5iguration). So, with aortic stenosis, there is an ejection murmur in systole, heard best at the right 2nd ICS, which radiates to the carotids, and the murmur intensity increases on expiration, and will probably hear an S4
b. Pulmonic Stenosis – heard best on left 2nd ICS, ejection murmur, and increases on expiration.
2. Diastolic murmurs: In diastole, mitral and tricuspid valves are opening.
a. Mitral Stenosis (problem in opening the valve) – who has the problem? Left atrium. Here’s the problem, the mitral valve doesn’t want to open but it has to in order to get blood into the left ventricle. So, the left atrium will get strong b/c it has an afterload to deal with – it becomes dilated and hypertrophied (the atrium) – which predisposes to atrial 5ib, thrombosis, and stasis of blood. So, the atrium is dreading diastole b/c it has to get the buildup of blood into the left ventricle. With the build up of pressure, the mitral valve “snaps” open, and that is the opening snap.
All the blood that was built up in the atrium comes gushing out into the ventricle, causing a mid-‐diastolic rumble. So, you have an opening snap followed by a rumbling sound (due to excess blood gushing into LV). With mitral stenosis, there is a problem with opening the valve, and therefore you are under 5illing the left ventricle, and therefore will be no HPY b/c you are under 5illing it. If you are having trouble getting blood into it, you are not overworking the ventricle; the left atrium has to do most of the work. Heard best at the apex and will increase in intensity on expiration. (same concept with tricuspid stenosis, just a different valve).