Heart Murmurs Flashcards
(33 cards)
Murmur vs Bruit
- When normal laminar blood flow within the heart is disrupted, an audible sound is created by turbulent blood flow.
- Outside of the heart audible turbulence is referred to as a bruit, while inside the heart it is called a murmur
Causes of murmurs
- Blood forced through tight area (stenosis): worse= louder except in HF (adequate pressures for murmurs not achieved so lessen/ disappear)
- Valvular insufficiency (backflow through incompetent valve creating turbulence when meets forward blood flow)
- Blood forced through congenital abnormality from chamber to another (ASD/ VSD)
- Increased flow of blood through normal valve in high output states (anaemia, thyrotoxicosis, sepsis)
What are the categories for describing heart murmurs?
- Timing
- Grading
- Shape
- Pitch
- Location
- Radiation
Timing of murmurs
-Systolic (between S1 and S2): aortic/ pulmonary stenosis vs mitral and tricuspid regurgitation
=mid/holo vs pan/ late
-Diastolic (between S2 and S1): a/p regurgitation vs m/t stenosis
=early/late
-Continuous: patent ductus arteriosus/ combination murmurs
Systolic murmurs
- Midsystolic (just after S1 and terminates just before S2)
- AS
- Pulmonary stenosis
- ASD
- Hypertrophic obstructive cardiomyopathy - Holosystolic (begins with or immediately after S1 and extends up to S2 so difficult to hear)
- MR
- Tricuspid regurgitation
- VSD - Late (begins significantly after S1)
- Mitral valve prolapse
Diastolic murmurs
- Early
- AR
- Pulmonary regurgitation
- Austin-Flint - Mid/late
- MS
- Tricuspid S
Grading systolic murmurs
- Barely audible
- Audible but soft
- Easily audible
- Easily audible and associated with a thrill
- Easily audible, associated with a thrill, and still heard with a stethoscope only lightly on the chest
- Easily audible, associated with a thrill, and still heard with the stethoscope off the chest
Grading diastolic murmurs
- Barely audible
- Audible but soft
- Easily audible
- Loud
-Intensity determined by volume/ velocity of blood through defect and distance between stethoscope and lesion
Shape of murmur
-Describes the change of intensity throughout the cardiac cycle =crescendo =decrescendo =crescendo-decrescendo =uniform
Pitch of murmur
-High pitched= large pressure gradient across the pathologic lesion (diaphragm)
-Low pitched= pressure gradient is low (bell)
=AS high pitched since there is usually a large pressure gradient between the LV and the aorta, may radiate to apex
=MS low pitched since there is a lower pressure gradient between the LA and the LV during diastole.
Location of murmur
- A = aortic valve post (right upper sternal border or RUSB)
- P = pulmonic valve post (left upper sternal border or LUSB)
- T = tricuspid valve post (left lower sternal border or LLSB)
- M = mitral valve post (apex)
- E = “Erb’s point”
Radiation of murmur
- AS frequently radiates to the carotid arteries
- MR radiates to the left axillary region.
- It is often difficult to distinguish if one murmur is radiating to multiple sites or if there are multiple murmurs present from many different causes.
- Dynamic auscultation and echocardiography is helpful in determining the exact lesion present.
Aortic Stenosis murmur
-High pitched
-Crescendo-decrescendo (diamond shaped)
-Aortic listening post and radiates to carotid, can also radiate to apex (Gallavardin dissociation)
=Dynamic auscultation/ echo to determine coexisting MR
-Worsens= LV failure= ejection fraction declines= insufficient force for turbulent flow= decreased intensity
-Worsens= longer for blood to eject through valve= later in systole
-Paradoxically split S2 as A valve heavily calcified, intensity of S2 declines
Pulmonary stenosis murmur
- Midsystolic high-pitched crescendo-decrescendo
- Pulmonary listening post and radiates slightly towards the neck (nor as widely as AS)
- Mild= early, severe= later
- Increasing intensity during inspiration due to increased venous return to R heart= greater flow across P valve
- Severe PS= decreased mobility of the pulmonic valve leaflets= softer P2
- Worsens= delayed closure (longer to eject blood)= widely split S2 heart sound that still exhibits inspiratory delay.
ASD murmur
-Increased flow through pulmonic valve= similar to PS
=Intensity of S2 unchanged/ accentuated if pulmonary hypertension develops
=S2 fixed-split (not widened in PS)
=Murmur not increased intensity with inspiration
Hypertrophic obstructive cardiomyopathy (HOCM) murmur
-High pitched
-Crescendo- decrescendo
-Mid systolic
-Left lower sternal border
-Does not radiate to carotids
-Distinguish from AS through dynamic auscultation
=HOCM more intense after standing and less intense after rapid squatting compared to AS
MR murmur
- High-pitched, “blowing” holosystolic murmur best heard at the apex
- Radiation depends on nature of disease but usually axilla
- Intensity of murmur does not increase with inspiration
Tricuspid regurgitation murmur
- High pitched, holosystolic murmur however it is best heard at the left lower sternal border and it radiates to the right lower sternal border
- Intensity increases significantly with inspiration (Carvallo’s sign)
VSD murmur
- Blood abnormally flows from the LV (high pressure) to the RV (low pressure) creating turbulent blood flow and a holosystolic murmur heard best at “Erb’s point”.
- The smaller the ventricular septal defect, the louder the murmur.
Mitral valve prolapse murmur
-Mid-systolic click usually followed by a uniform, high-pitched murmur.
-The murmur is actually due to mitral regurgitation that accompanies the mitral valve prolapse, thus it is heard best at the cardiac apex.
-Mitral valve prolapse responds to dynamic auscultation.
=Extends with sudden standing and decreases with sudden squatting
AR murmur
- Soft, high-pitched, early diastolic decrescendo murmur usually heard best at the 3rd intercostal space on the left (Erb’s point)/ right upper sternal border if due to aortic root disease at end expiration with the patient sitting up and leaning forward.
- Worsens= pressure between the left ventricle and the aorta equalize much faster, thus the murmur becomes significantly shorter
- Systolic ejection murmur may be present in people with severe aortic regurgitation at the right upper sternal border simply due to the large stroke volume passing through the aortic valve with each systolic contraction of the LV
Austin Flint murmur
In people with aortic regurgitation, an early diastolic rumble may also be heard at the apex due to the regurgitant jet striking the anterior leaflet of the mitral valve causing it to vibrate.
Pulmonic regurgitation murmur
- Often indistinguishable from that of AR.
- soft, high-pitched, early diastolic decrescendo murmur heard best at the pulmonic listening post (LUSB).
- Increases in intensity during inspiration, unlike that of AR.
- Graham-Steell murmur
MS murmur
- Uniquely shaped, low-pitched diastolic murmur best heard at the cardiac apex.
- Opening of the mitral valve= “opening snap” due to the high left atrial pressures, which is immediately followed by a decrescendo murmur as blood flows passively from the left atrium to the left ventricle through the stenosed mitral valve creating turbulence.
- Immediately before the S1 sound, active left ventricular filling occurs when the left atrium contracts and forces more blood through the stenosed mitral valve creating a late diastolic crescendo murmur.
- In the presence of AF, the active left ventricular filling phase does not take place and the latter part of the MS murmur disappears.
- Worsens= left atrial pressure increases forcing the mitral valve open earlier in diastole= opening snap occurs earlier as does the initial decrescendo part of the murmur.
- The opening snap and murmur of mitral stenosis also respond to dynamic auscultation.
