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Flashcards in Physiology-Heart Sounds Deck (23)
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Through which structures do you hear low frequency heart murmurs? High frequency heart murmurs?

Aortic and pulmonary (semilunar valves) are where you have high frequency heart murmurs. Atrioventricular valves (mitral and tricuspid) are where you hear low frequency murmurs.


You are listening to the heart sounds of you lab partner and hear the typical "lub dub". Why is there a pause after the dub?

The dub indicates diastole where ventricles are filling. This is a longer pause to ensure they fill with enough blood to pump out of the heart.


What is responsible for the little pressure kick indicated by the heart in the left ventricle?

The left atria contracts during ventricular diastole and increases cardiac output by up to 30%.


What is happening during the increase in pressure indicated by the heart below?

Isovolumetric contraction. The ventricles contract, but blood has not yet moved because the pressure has not yet exceeded that of the aorta or pulmonary artery.


How long does it take for the heart to eject 70% of ventricular blood during systole?

The 1st 1/3 of systole. This is the period of rapid ejection.


What valves close just prior to where the little heart is at and what valves open just after where the little heart is at?

This is the period of isovolumetric contraction that is preceded by closing of the aortic and pulmonic valves. When the left ventricular pressure becomes less than the left atrial pressure, the mitral valve open and blood again fills the ventricle.


When does most ventricular filling occur?

During the rapid filling phase right after the AV valves open (v-wave). Most filling occurs during the first 1/3 of diastole.


What is happening during this final phase where the heart is?

Diastasis. There is reduced ventricular filling with blood continuing to empty into atria. This phase ends with atrial kick.


What happens at the point where the little heart is?

Dicrotic notch (incisura). This is when the pressure in the aorta exceeds that of the left ventricle and the aortic valve shuts and isovolumetric relaxation begins.


When is atrial pressure the highest? What can it be followed by immediately?

It is highest during the a wave (atrial kick/systole) where the atria contract. Pressure can get up to about 15 mmHg. The a wave is followed by atrial relaxation where ventricles start isovolumetric contraction that can cause backward bulging of tricuspid valve and increased atrial pressure, the c wave.


What is responsible for the x decent and the v wave?

The x decent is caused by ventricular emptying of content. The v wave is caused by a slow increase in atrial pressure from slow atrial filling of venous blood while the AV valves are closed.


What may a dramatically increased V wave indicate?

Regurgitation of blood through the tricuspid valve into the right atria, causing an even greater increase in atrial filling during atrial diastole.


What happens at the y descent?

AV valves open and atria drain rapidly into the ventricles.


How do you calculate stroke volume and ejection fraction?



What are the noises always heard in the heart?

Valves closing (S1 = low frequency closing of AV valves and S2 = high frequency closing of semilunar valves). In diseased states you can hear valves opening.


What are the noises sometimes heard?

S3 = rapid ventricular filling. S4 = atrial kick.


What sound represents the dicrotic notch?

S2. This is when the aortic/pulmonic valves close because arterial pressure exceeds that of ventricular pressure.


What sound happens just prior to the c wave?

S1. This is when the AV valves close right before ventricles contract and create that isovolumetric pressure that creates the c-wave.


What heart sound can be a sign of left ventricular failure? Why is this?

S3. The sound you hear is early termination of left ventricular filling. "What the hell".


What heart sound goes with this wave?

S4. It is rare and happens when the atria have to contract extra hard in order to overcome an abnormally stiff hypertophic ventricle. "a-STIFF-wall (a S4, stiff S1, wall S2)


What makes the S2 heart sound split when you take a big deep breath?

When you take a deep breath, the lungs fill with blood, lessening the left side stroke volume and increasing the right side stroke volume. This results in A2 happening earlier and P2 happening much later.


What do you know about an S4 exaggerated with inspiration?

It is a right heart problem.


Just take a look at this image and understand it. 

Do you get it?

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