Evaluating Murmurs

Question 1

how are murmurs classified by timing in the cardiac cycle?

Answer 1

systolic murmurs: begin with/after S1, end at/before S2
diastolic murmurs: begin with/after S2, end at/before S1
continuous murmurs: always present

holosystolic: constant through systole, may obscure S1
mid-systolic: crescendo-decrescendo in mid systole
late systole: decrescendo, beginning mid systole

early diastolic: decrescendo, beginning at S2
mid-diastolic: decrescendo-crescendo in mid-diastole

Question 2

what kind of murmur does mitral or tricuspid valve regurgitation produce?

Answer 2

holosystolic (continuous throughout systole, may obscure S1)

*holosystolic murmur can also be due to ventricular septal defect

Question 3

what are 3 possible causes of a holosystolic murmur?

Answer 3

1. mitral regurgitation
2. tricuspid regurgitation
3. ventricular septal defect

Question 4

what kind of murmur is produced by an aortic or pulmonary stenosis?

Answer 4

mid-systolic murmur (crescendo-decrescendo pattern)

note that the crescendo-decrescendo sound follows the pressure curve of the aorta during contraction

*mid-systolic murmur can also be produced by obstructive cardiomyopathy

Question 5

what are 3 possible causes of a mid-systolic murmur?

Answer 5

1. aortic stenosis
2. pulmonary stenosis
3. obstructive cardiomyopathy

Question 6

what does a late systolic murmur indicate?

Answer 6

mitral valve prolapse

Question 7

what kind of murmur does a mitral valve prolapse produce?

Answer 7

late systolic murmur

Question 8

what might an early diastolic murmur indicate? (2)

Answer 8

1. aortic regurgitation
2. pulmonic regurgitation

Question 9

what kind of murmur is produced by an aortic or pulmonic regurgitation?

Answer 9

early diastolic murmur with decrescendo

Question 10

what does a mid-diastolic murmur indicate?

Answer 10

mitral stenosis

Question 11

what kind of murmur does mitral stenosis produce?

Answer 11

mid-diastolic

Question 12

where do murmurs caused by aortic stenosis and mitral regurgitation radiate to, respectively?

Answer 12

aortic stenosis radiates to the neck

mitral regurgitation radiates to the axilla

Question 13

how is the intensity of heart murmurs graded?

Answer 13

1/6: less intense than S1/S2
2/6: same intensity as S1/S2
3/6: more intense than S1/S2

with thrill (feeling of turbulence on chest wall):
4/6: louder than grade 3
5/6: heard with stethoscope partially off chest
6/6: heart by ear

Question 14

how can you distinguish between a murmur caused by mitral and tricuspid regurgitation?

Answer 14

listen on inspiration —> decreased intrathoracic pressure/ R atrial pressure, increased venous return/ R side volume —> increased intensity of R-side murmurs

[also recall inspiration decreases blood to L side of heart]

therefore, if murmur is louder with inspiration —> tricuspid regurgitation

Question 15

What maneuver can you use to distinguish between a murmur caused by mitral regurgitation and aortic stenosis?

Answer 15

hand grip maneuver —> increased afterload/arterial pressure

with mitral regurgitation: causes more backflow, murmur is louder (more intense)

with aortic stenosis: causes less flow across valve, murmur is softer (less intense)

therefore, louder with handgrip = mitral regurgitation

Question 16

what is the Valsalva maneuver

Answer 16

increase intrathoracic and intraabdominal pressure —> decreased venous return to the heart —> RV/LV volumes decreased

in most cases, murmur intensity will also decrease (but some will not - giveaway)

Question 17

how can standing to squatting be used to diagnose a specific murmur?

Answer 17

standing to squatting —> increased venous return (decreased effect of gravity), increased afterload (causes kinks in arteries) —> increased volume in the heart makes most murmurs louder