Heart valves and sounds Flashcards
If you are feeling someone’s carotid pulse, it will immediately follow […].
S1
The S2 heart sound can sound “split”. What are the conditions during which this can happen and what do they mean clinically?
- Spiltting upon inspiration is normal, but likely to only be heard in the pulmonic ascultory area
- “Fixed” splitting is abnormal and when present it almost always indicates an atrial septal defect (ASD). A fixed split S2 occurs when there is always a delay in the closure of the pulmonic valve.
Which type of murmurs are more common and why?
Left side more common than right because of high pressure they are under, more prone to injury
What is the S3 heart sound?
What is the S4 heart sound?
What are some easy ways to remember the difference between regurgitation and stenosis murmurs?
Regurgitation is a closing problem, stenosis is an opening problem
What murmurs can be heard during systole?
Mitral (L) / tricuspid (R) valve regurgitation
Aortic (L) / pulmonic (R) valve stenosis
Mitral valve prolapse
What murmurs are audible during diastole?
Aortic (L) / pulmonic (R) regurgitation
Mitral (L) / Tricuspid (R) stenosis
Describe what is happening to produce an aortic stenosis murmur.
Systole begins with the closing of the mitral valve. During the first half of systole, the heart contracts without change in volume and this increases the pressure in the ventricle. The aortic valve opens when the pressure in ventricle > pressure in aorta. When there is aortic stenosis (narrowing), the AV doesn’t open fully, so, compared to a normal heart, the same volume of blood at the same pressure is forced out of a smaller opening and this creates turbulent flow that is heard in the form of a murmur.
Describe the sound of an aortic stenosis murmur.
Systolic ejection murmur with early systole ejection click
Note: click is caused by rapid, but incomplete opening of valves and blood initially hitting valve.
Describe the shape of an aortic stenosis murmur.
Crescendo-decrescendo (diamond shaped) murmur
Sound intensifies as blood leaves AV while left ventricle is still contracting and pressure is still rising. When LV stops contracting and pressure begins to drop the sound dissipates.
Other than the left upper sternal border, where else can aortic stenosis murmurs commonly radiate (be heard)?
Carotid arteries
What are the similarities and differences between aortic stenosis murmur and pulmonic stenosis murmur?
Same shape
Same sound
Both can have click
Same rationale behind what causes the murmur
PV murmur does not radiate to carotids
What type of murmur is mitral regurgitation?
Pansystolic
Describe what is happening in the left side of the heart to produce mitral regurgitation.
This is a systolic murmur. During normal systole, the MV should be closed fully because P ventricle > P atrium and it is a one way valve. However, defects in the valve can cause it to not fully close during systole. Thus, when the LV begins contracting during systole, blood can flow into the L_atrium. Eventually, P_LV > P aorta and the aortic valve will open. However, blood will continue to flow through the MV into L atrium because pressure in LV remains higher than pressure in L atrium during all of systole. This is why the sound can be heard during all of systole.
What compensations occur in the left atrium (right atrium) when a person has a chronic mitral (tricuspid) valve regurgitation murmur?
Blood flow from LV into LA during systole increases the P in the LA. In response, over time the LA will dilate to accomodate the increasing volume of blood and increasing pressure. This maintains the compliance of the LA.
Same is true for right side.
What is the shape of an aortic regurgitation murmur?
Flat pansystolic
Describe what is happening in the LV to cause the murmur heard with mitral valve prolapse.
This is a systolic murmur. During normal systole, the MV should be closed fully because P ventricle > P atrium and it is a one way valve. However, defects in the valve can cause it to billow up into the LA when the pressure in the LV increase during isovolumetric contraction. This causes the chordae tendinae that are attached to the valve to tense up and the tensing of these structures causes an audible “click”. In this billowed position, it is possible for blood to flow back into the LA as well which would produce sounds similar to that of mitral regurgitation for the remainder of systole.
What is the shape of a mitral valve prolapse murmur?
Mid-systolic click with late systolic murmur
Non-ejection murmur
Describe what is happening in the left side of the heart to produce the sound heard during aortic regurgitation murmur.
During diastole, AV should be closed and MV should be open. Blood should be entering LV from LA via MV. In ARM, the AV does not close completely. As such, at the very beginning of diastole, the P aorta > P ventricle so there will be intense blood flow into LV from aorta. However, over time, the P ventricle will increase due to filling from the LA and aorta so the pressure difference will lessen and the murmur will become softer. This causes the decrescendo sound heard with the murmur.
Describe the shape of an aortic regurgitation murmur.
Early diastolic decrescendo murmur
What type of murmur is mitral stenosis?
Early diastolic decrescendo murmur with opening snap and pre-systolic accentuation
OR
Opening snap followed by mid-diastolic rumble
Describe what is happening in the left side of the heart to cause a mitral stenosis murmur.
This is a diastolic murmur. During normal diastole, the MV opens to allow blood to flow down pressure gradient from LA to LV. However, when MV is stenotic, the valve is narrowed and cannot open as widely. This causes turbulent flow that is heard audibly as a murmur. When the MV is pulled open by the chordae tendinae, there is an opening snap that occurs because the valve is more rigid and can’t open fully and blood is rushing against it from LA to LV. The sound is more intense in the beginning of diastole because the pressure gradient between the LA and LV is greatest at the beginning of diastole during rapid filling. The sound becomes softer as diastole continues. Toward the end of diastole, the LA contracts to push the last bit of blood into the LV and this causes a brief increase in sound intensity right before systole.
