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PHYSICAL EXAMINATION FOR CARDIAC MURMURS
André N. Sofair, M.D., M.P.H.
WEEK 21
Learning Objectives:
1. To understand the grading of murmurs
2. To understand the most common systolic and diastolic murmurs
3. To discuss the appropriate physical examination maneuvers to better differentiate
murmurs
A Historical Note:
Laënnec invented the stethoscope in 1816 when he needed to examine a woman with a large
bosom who complained of chest pain. Too shy to put his ear to the woman’s chest, he rolled a
paper booklet into a large cylinder, put it onto her chest with his ear at the other end, and heard
a murmur. He called the instrument a stethoscope, meaning “breast spy.” (Am J Med 2000;
108: 614-620)
Current “state of the art”:
Recent work has demonstrated that cardiac auscultatory skills of internal medicine and family
medicine trainees are poor (They were inaccurate 80% of the time while attempting to identify
digitized sounds taken directly from patients.) (JAMA 1997; 278: 717-722). In the hands and
ears of cardiologists, however, the examination of the heart is quite precise, with a sensitivity
of 70% and a specificity of 98% (American Journal of Cardiology 1996; 77: 1327-1331).
Data on which patients should undergo a physical examination of the heart is limited. A
prudent practice would be to examine all patients where a cardiovascular database is desired,
those with known or suspected heart disease, and all patients in the preoperative setting,
especially where prophylaxis for endocarditis might be indicated.
Data on which murmurs should be further evaluated by echocardiogram are also limited.
Benign murmurs tend to be seen in women, those under age 35, and are Grade 2 or softer
(JGIM 1994; 9: 479-484). In my opinion, all other murmurs, including all diastolic murmurs
and murmurs suggestive of hypertrophic obstructive cardiomyopathy should be evaluated
further.
Grading of murmurs:
Grade 1 is a murmur not heard immediately on auscultation. Grade 2 is heard easily but not as
loudly as Grade 3. Grade 3 is a very loud murmur. Grade 4 murmurs are associated with a
palpable thrill. Grade 5 murmurs are audible with one edge of the stethoscope on the chest and
Grade 6 is audible with the stethoscope completely off of the chest (JAMA 1999; 281: 22312238).
CASE ONE:
A 65-year-old man is seen with complaints of shortness of breath upon exertion. On
examination, his blood pressure is 136/78 and his pulse rate is 90 and regular. He has a
normal jugular venous contour and pressure. His lungs are clear. His point of maximal
impulse is in the 5th intercostal space, is laterally displaced to the anterior axillary line,
and is enlarged. On auscultation, he has a Grade 3 holosystolic murmur best heard at the
apex. It does not change during the respiratory cycle and is accentuated by the Valsalva
maneuver. Splitting of the second heart sound is normal, and the pulmonic component of
the second heart sound is normal in caliber.
Questions:
1. What is your differential diagnosis for this murmur?
The holosystolic quality of the murmur suggests a regurgitant murmur of either the
mitral or tricuspid valve. The normal venous contour and pressure, the lack of a
pulsatile liver, and the abnormality of the left ventricular impulse all make a left-sided
murmur more likely. A VSD or ASD are possible, but the normal quality and splitting
of the second heard sound make these unlikely (both are often associated with a
prolonged split and a louder P2 component because of increased flow across the
pulmonic valve as well as the association with pulmonary hypertension in cases with
advanced presentation).
2. What is the importance of the lack of change in the intensity of the murmur
during the respiratory cycle?
Right-sided murmurs typically increase with inspiration due to increased venous return
to the right side of the heart due to the negative intrathoracic pressure associated with
this phase of the respiratory cycle. To detect this, I usually listen where the murmur is
just barely audible as I can better appreciate subtle changes in intensity associated
with the maneuver. I also listen during quiet breathing, as asking the patient to “take a
deep breath” often results in the patient performing a Valsalva maneuver at the same
time, which has the undesired effect of decreasing venous return.
The murmur is a left sided murmur suggestive of mitral regurgitation.
3. What is the implication of the augmentation of the murmur with Valsalva
maneuver?
The later stages of the Valsalva maneuver (you must wait for stage II of the Valsalva,
which begins 10-20 seconds into the maneuver) will decrease venous return, thereby
decreasing pre-load to both ventricles (Braunwald, E. Heart Disease, 6th ed. Saunders,
Phila. 2001). Only two murmurs augment with a diminished preload. The first is
hypertrophic obstructive cardiomyopathy (with diminution in preload, the left
ventricular free wall and the hypertrophied septum are more likely to abut one another
and create turbulence during systolic ejection of blood and also the anterior leaflet of
the mitral valve is more likely to be drawn into the left ventricular outflow tract,
causing mitral regurgitation). The second condition is mitral valve prolapse, with or
without regurgitation. A diminished preload will decrease cavity size, making the
valves relatively more redundant and more likely to balloon back into the atrium
without co-apting normally. This murmur is suggestive of mitral valve regurgitation
secondary to mitral valve prolapse as was demonstrated by his echocardiogram. To
best hear this murmur, have the patient lie down and perform a Valsalva maneuver or
ask them to stand. The murmur should be audible over the precordium or at the apex.
4. Are there any other abnormalities of the cardiac examination that you might
expect to find with this cardiac condition?
You might expect to hear a midsystolic click (due to the prolapse) which is mobile with
different maneuvers. Maneuvers, which diminish pre-load (going from squatting to
standing, Valsalva), will accentuate the click and move it closer to S1. This mobility is
not found with valvular ejection clicks (usually due to opening of the pulmonic or aortic
valve) where the position in the cardiac cycle should remain constant. With late stages
of mitral valve prolapse with regurgitation, this click may be absent.
Transient arterial occlusion (inflating two blood pressure cuffs to 20-40 mm above
systole in both upper arms) will also accentuate the murmur of mitral regurgitation by
augmenting afterload.
CASE TWO:
A 23-year-old woman is in the hospital for Group A streptococcal sepsis related to
injection drug use-related septic thrombophlebitis of her axillary vein. Her admission
cardiovascular examination and a transthoracic echocardiogram were unremarkable.
Although her blood cultures rapidly turned negative, she is noted during her second week
of hospitalization to have both a systolic and diastolic murmur (both Grade 3) heard best
at the 2nd right intercostal space. Her jugular venous contour and both left and right
ventricular point of maximal impulses are normal. Her blood pressure is 140/40 and her
pulse volume is hyperdynamic. There are no other stigmata of endocarditis, and her
CBC is normal.
5. What is your differential diagnosis for these murmurs?
Their location around the base of the heart suggests either an aortic or a pulmonic
murmur. The location over the right side of the chest, the high pulse pressure (greater
than 50% of systolic), and the hyperdynamic pulse are more consistent with a left sided
lesion.
The combined systolic and diastolic murmurs suggest aortic stenosis/sclerosis and
aortic insufficiency. The fact that she had no murmur of aortic stenosis audible on
initial examination and the fact that her echocardiogram also failed to reveal this
suggests an acquired lesion related to her bacteremia. The hyperdynamic circulatory
state associated with aortic insufficiency may produce a systolic flow murmur across a
non-stenotic aortic valve (JAMA 1999; 281: 2231-2238). This is a similar
phenomenon to the benign flow murmurs associated with pregnancy, hyperthyroidism,
anemia, or fever.
The patient’s repeat echocardiogram revealed severe aortic regurgitation with a
perivalvular abscess. To best hear this murmur, place the patient in the sitting
position, have them exhale (to remove air from the lungs which may muffle the murmur)
and listen over the base of the heart.
6. What other manifestations may be associated with this murmur?
As in the case of mitral regurgitation, transient arterial occlusion will augment the
murmur of aortic insufficiency. Other associated signs include the deMusset head
bobbing sign (forward head-bobbing with each pulse) and pistol shot femoral sounds
(heard with the diaphragm over the femoral arteries), both due to increased stroke
volume. Quinke’s pulse (pulsations of the nail bed blood vessels visible with light
compression of the nail plate) has not been adequately studied.
7. What is the Austin-Flint murmur?
This is a diastolic sound heard over the apex of the heart in the setting of aortic
regurgitation, which may mimic the murmur of mitral stenosis. It is heard best with the
patient in the left lateral decubitus position and is caused by the regurgitant jet striking
the apex or causing the anterior leaflet to close and cause functional but clinically
insignificant mitral stenosis. It may be differentiated from mitral stenosis by the
absence of the mitral opening snap associated with mitral stenosis and the softening of
S1 associated with aortic insufficiency (and not mitral stenosis) due to higher left
ventricular preload closing the mitral valve in the former case.
CASE THREE:
An 80-year-old woman is found to have a Grade 2 systolic murmur, which is heard best
over the right 2nd intercostal space, radiating to both carotids. It is early peaking, has no
diastolic component, and decreases in intensity with Valsalva maneuver. You are able to
hear both components of S2 normally, and her carotid pulse volume is normal. Her left
ventricular point of maximal impulse is normal, and she has no apical-carotid delay (her
apical systolic impulse and her radial pulse occur simultaneously).
8. What is this murmur? Are her findings worrisome?
This murmur suggests either aortic sclerosis or stenosis. The fact that she has an
early-peaking murmur, has a normal carotid pulse volume, and that you can hear both
components of the second heart sound suggests that her valve is not critically stenotic
(usually defined as a valve are of less then 0.8 cm2or a peak transvalvular gradient of
more than 50 mm Hg (JAMA 1997; 277: 564-571)). I generally confirm my findings
with an echocardiogram unless the murmur appears to be a benign flow murmur
(usually a grade 1-2 systolic murmur heard in the left upper sternal border without
radiation). An echocardiogram revealed a calcified tricuspid aortic valve with
sclerosis but no significant stenosis.
9. What would you have considered had the murmur increased in intensity with a
Valsalva maneuver?
As mentioned earlier, only two murmurs should increase in intensity with Valsalva:
mitral valve prolapse and hypertrophic cardiomyopathy. The location of this murmur
would make mitral valve prolapse very unlikely. Other associated physical findings
with hypertrophic obstructive cardiomyopathy include a double carotid impulse (due to
the initial systolic outflow of blood, transient outflow obstruction, and second outflow
of blood) and a diminution in the murmur with transient arterial occlusion outlined
above as slowing the contraction of the ventricle can limit turbulence.
References:
1. Etchells, E, et.al. Does this patient have an abnormal systolic murmur? JAMA.
1997; 277: 564-571.
2. Choudhry, NT, et.al. Does this patient have aortic regurgitation? JAMA. 1999;
281: 2231-2238