Hear Murmurs

Question 1

What causes a heart murmur and what are bruits?

Answer 1

Murmurs are produced by turbulent blood flow, a bruit is a murmor but heard at some place else besides the heart.

Question 2

What is a predictor of turbulent flow of blood?

Answer 2

Reynold’s Number N(r), the higher the number the more likely the murmur. Formula: N(r) = ((density of fluid)(diameter of vessel)(velocity of flow))/viscosity of fluid.

Question 3

What is the formula of reynold’s number?

Answer 3

N(r) = ((density of fluid)(diameter of vessel)(velocity of flow))/viscosity of fluid.

Question 4

What are the main causes of murmurs?

Answer 4

Increased velocity of blood whether it be hyperdynamic states like sepsis or hyperthyroidism or through a narrowed vessel (i.e. through stenosis), It can also be caused by decreased viscosity, as caused by anemia.

Question 5

How does the blood viscosity decrease?

Answer 5

Via anemia.

Question 6

How does the diameter of a vessel or valve decrease?

Answer 6

Valvular stenosis, coarctation of the aorta, or ventricular septal defect.

Question 7

How does the velocity of blood increase if there is no narrowing?

Answer 7

Hyperdynamic states like sepsis and hyperthyroidism?

Question 8

What can cause regurgitation across an incompetent valve?

Answer 8

Valvular regurgitation.

Question 9

What does the timing of murmurs tell us?

Answer 9

Whether it is systolic, diastolic, or both, in terms of origin.

Question 10

What are examples of systolic murmurs?

Answer 10

“Flow murmors” i.e. anemia, hyperdynamic states. Aortic/pulmonic stenosis. Mitral/tricuspid regurgitation. Ventricular septal defect. Aortic outflow tract obstruction.

Question 11

Examples of diastolic murmors?

Answer 11

Aortic/pulmonic regurgitation and mitral/tricuspid stenosis. Aortic regurgitation is most common in adults.

Question 12

Examples of continuous murmors (present in systole and diastole)?

Answer 12

Patent ductus arteriosis in infancy. However, aortic stenosis and aortic regurgitation at the same time might give the illusion of a continuous murmor.

Question 13

Where is (theoritically) aortic murmurs heard best?

Answer 13

2nd ICS just to the right of sternum, however this can actually be heard basically anywhere in the chest.

Question 14

Location where pulmonic HS is theoritically the loudest? Tricuspid and mitral?

Answer 14

P: 2 ICS on Left of sternum. Tri: 4th ICS on LS. M: 5 ICS on L mid clavicular line.

Question 15

What is the concept of radiation with murmors?

Answer 15

Basically the direction of the turbulent blood flow is where it “radiates” and this sound is not heard over the heart (as the sound it makes is much louder further downstream due to physics.

Question 16

What are the three “shapes” of the murmor that can be heard?

Answer 16

Crescendo-Decrescendo (increase in sound, peak, decrease in sound), decrescendo (from loud to soft), and uniform (holosystolic).

Question 17

Which shape of murmur is heard during systole, and which are heard during diastole?

Answer 17

Cres/Decres and uniform heard during systole, decres heard during diastole.

Question 18

What causes the loudness or softness of sound?

Answer 18

The pressure gradient between the vessels involved, i.e. between LV and aorta there shouldn’t be a massive difference as we see in aortic stenosis, thus in the areas with the most difference in pressure we hear the loudest noise, because thats where velocity is highest.

Question 19

What causes the decrescendo sound we hear in aortic regurg?

Answer 19

Blood flows back into the LV from the aorta, so pressure in the aorta actually decreases as the heart sound progresses leading to the decrescendo.

Question 20

What kind of sound do we hear in mitral regurgitation and why?

Answer 20

Uniform murmur during systole, during which time there is a gradient between LV and LA where blood flows back into the LA from LV. The pressure gradient stays constant during systole, so there is neither a crescendo nor decrescendo heard during systole.

Question 21

Sound of mitral stenosis severe and mild?

Answer 21

Severe sounds heard in the diastole, and in severe case its uniform, in mild cases its decrescendo.

Question 22

What are the 3 types of pitch heard in a murmur and why are they caused?

Answer 22

High pressure gradient (i.e. VSD) has high pitch, high volume but low pressure i.e. mitral stenosis gives low pitch, high pressure high volume in aortic stenosis gives “harsh” pitch caused by a combination of both high and low pitch.

Question 23

What are the intensities of murmurs graded as?

Answer 23

1-6, 1 is barely heard, 2 is heard but faint, 3 is loud, 4 is associated with a thrill, 5 you can hear with stethoscope barely in contact, 6 you can hear without a stethoscope.

Question 24

What is the purpose of fist clenching manuever?

Answer 24

It should increase afterload, so mitral regurg intensity will increase, but aortic stenosis intensity will either decrease or stay unchanged. Might enhance the sounds of aortic regurg as well.

Question 25

What is the point of the squatting or supine manuever?

Answer 25

Increase venous return and stroke volume, so aortic stenosis intensity increases whereas hypertrophic obstructive cardiomyopathy will decrease in intensity.

Question 26

What is ejection murmur and flow murmur?

Answer 26

Ejection murmur is blood flowing forward through the semilunar valves during systole, flow murmur is blood flowing forward through morphologically normal valves.

Question 27

Without feeling the pulses and minus fast tachycardias, how can we tell the difference between systole and diastole?

Answer 27

Systole is shorter than diastole, it takes longer for the ventricles to fill up than it takes for the ventricles to blast out the blood.

Question 28

High pitch systolic murmur found at the apex of the heart that is unoform or holosystolic.

Answer 28

Mitral regurgitation.

Question 29

Murmur at R 2ICS, systolic, cres/decres, and harsh.

Answer 29

Aortic stenosis.

Question 30

4th L ICS, diastolic, decrescendo, “blowing” in nature.

Answer 30

Aortic regurg.