11/13/24, 7\:05 PM Guide | Heart murmurs

Heart murmurs

Table of contents

Introduction

A heart murmur is a sound produced due to turbulent blood
common heart murmurs and the underlying aetiology.

Cardiac cycle

The cardiac cycle refers to a series of physiological events making up a single heartbeat. The cycle involves contraction
(systole) and relaxation (diastole) of the atria and ventricles to e
The cardiac cycle starts with the atria and ventricles in diastole. Blood enters the right atrium (from the vena cava) and the left
atrium (from the pulmonary vein). At this point, the mitral and tricuspid valves are open. This allows blood to
right ventricle and left ventricle from the atria. The aortic and pulmonary valves are shut, which prevents an abnormal back
of blood into the ventricles from the aorta and pulmonary artery.
The next stage of the cycle is atrial systole, contraction of the atria to
Ventricular systole occurs as the ventricles contract, increasing the pressure within the ventricles. The increased pressure
causes the closure of the mitral and tricuspid valves, this prevents regurgitation of blood from the ventricles into the atria.
At this point, the volume of blood within the ventricles remains constant as the aortic and pulmonary valves have not yet
opened. This phase of ventricular systole is called isovolumetric contraction.
Eventually, the pressure within the ventricles exceeds the pressure in the pulmonary artery and aorta causing the pulmonary
and aortic valves to open. Blood is ejected from the ventricles during ventricular ejection phase.
The ventricles then begin to relax following contraction (ventricular diastole). The drop in pressure within the ventricle causes
the aortic and pulmonary valves to close, to prevent back
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Figure 1. An overview of the cardiac cycle [1]

Normal heart sounds

Normal heart sounds are caused by the closure of heart valves.

First heart sound (S1)

The
and a peripheral pulse is felt at the same time (or shortly after) S1.

Second heart sound (S2)

The second heart sound (S2) is caused by the closure of aortic and pulmonary valves. It marks the end of ventricular
systole and the start of diastole.
The pulmonary valve may close just after the aortic valve. Closure of the pulmonary valve just after the aortic valve is
prolonged during inspiration, or in defects which cause more blood to be pumped out of the right ventricle.
Therefore, S2 may not always be heard as one discrete sound but may be mu

Heart sounds and the cardiac cycle

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Figure 2. Events of the cardiac cycle [2]

How to approach heart murmurs

It is important to have a structured approach to interpreting heart murmurs during a cardiovascular examination.
If a murmur is heard during auscultation, consider the following questions\:
When during the cardiac cycle is the murmur heard?
What are the characteristics of the murmur? What is the intensity (Table 1)?
Is the murmur heard loudest using the bell or the diaphragm of the stethoscope?
Where is the murmur heard the loudest?
Do any manoeuvres exaggerate the murmur?
Heard loudest on inspiration or expiration?
Does the murmur radiate?
Table 1. The Levine scale for grading cardiac murmurs according to intensity.
3
Grade Description
One Very faint. Heard by an expert in optimum conditions
Two Heard by a non-expert in optimum conditions
Three Easily audible, no thrill
Four A loud murmur, with a thrill
Five Very loud, often heard over a wide area, with thrill
Six Extremely loud, heard without a stethoscope
A thrill is a palpable vibration caused by turbulent blood
anterior chest wall during cardiovascular examination.

Aortic stenosis

Aortic stenosis (AS) refers to a tightening of the aortic valve at the origin of the aorta.
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Aortic stenosis is associated with an ejection systolic murmur heard loudest over the aortic valve. The murmur is described as
having a ‘crescendo-decrescendo’ quality (it appears as diamond-shaped on a phonogram). The murmur of aortic stenosis
commonly radiates to the carotid arteries.

Aetiology

Causes of aortic stenosis include\:
Calci
adults.
Congenital abnormality of the aortic valve\: the aortic valve is normally composed of three cusps (known as a tricuspid valve),
but in some cases, individuals have only two cusps (known as a bicuspid valve) which predisposes them to the
development of AS as well as aortic regurgitation.
Rheumatic heart disease\: a rare cause of AS in developed countries.

Clinical features

Typical features of an aortic stenosis murmur include\:
Ejection systolic murmur heard loudest over the aortic area
Radiates to the carotid arteries
Loudest on expiration and when the patient is sitting forwards
Other clinical features of aortic stenosis may include\:
Slow rising pulse with narrow pulse pressure
Non-displaced, heaving apex beat (if present indicates left ventricular hypertrophy)
Reduced or absent S2 (a sign of moderate-severe aortic stenosis)
Reverse splitting of S2\: aortic valve closes after pulmonary valve (due to the longer time required for blood to exit the left
ventricle)
For more information, see the Geeky Medics guide to performing a focussed aortic stenosis examination.

Mitral regurgitation

Mitral regurgitation (MR) occurs when there is back
(through the mitral valve) during ventricular systole.
Mitral regurgitation is associated with a pansystolic murmur heard loudest over the mitral area and radiating to the axilla.

Aetiology

Mitral regurgitation can be either acute or chronic.
Causes of mitral regurgitation include\:
Infective endocarditis
Acute myocardial infarction with rupture of papillary muscles
Rheumatic heart disease
Congenital defects of the mitral valve
Cardiomyopathy

Clinical features

Typical features of mitral regurgitation murmur include\:
A pansystolic murmur heard loudest over the mitral area
Radiation of the murmur to the axilla
Loudest on expiration in the left lateral decubitus position
Other clinical features may include\:
Displaced, hyperdynamic apex beat
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Aortic regurgitation

Aortic regurgitation (AR) occurs when there is a back
diastole.
Aortic regurgitation is associated with an early diastolic murmur heard loudest at the left sternal edge

Aetiology

Aortic regurgitation can be either acute or chronic. Chronic AR is often asymptomatic.
AR can occur due to a disease process a
Diseases a
Congenital bicuspid aortic valve
Rheumatic heart disease
Infective endocarditis
Causes of aortic root dilatation include\:
Aortic dissection\: can result in acute aortic regurgitation
Connective tissue diseases (e.g. Marfan's syndrome)
Aortitis

Clinical features

Typical features of an aortic regurgitation murmur include\:
Decrescendo early diastolic murmur
Heard loudest at the left sternal edge (the direction that the turbulent blood
area
Austin Flint murmur\: a low pitched rumbling mid-diastolic murmur heard best at the apex. This is caused by the regurgitated
blood through the aortic valve mixing with blood from the left atrium, during atrial contraction. An Austin Flint murmur is a
sign of severe aortic regurgitation.
Other clinical features of aortic regurgitation may include\:
Collapsing pulse (a 'water hammer pulse' with wide pulse pressure)
Displaced, hyperdynamic apex beat
Eponymous clinical signs of aortic regurgitation
There are many eponymous clinical signs associated with aortic regurgitation. These include\:
Corrigan’s sign\: visible distention and collapse of carotid arteries in the neck
De Musset’s sign\: head bobbing with each heartbeat
Quincke’s sign\: pulsations are seen in the nail bed with each heartbeat when the nail bed is lightly compressed
Traube’s sign\:
‘pistol shot’ sound heard when stethoscope placed over the femoral artery during systole and diastole
Muller’s sign\: uvula pulsations are seen with each heartbeat

Mitral stenosis

Mitral stenosis (MS) involves narrowing of the mitral valve, which results in decreased
and increased left atrial pressure (due to incomplete left atrial emptying).
Mitral stenosis is associated with a low-pitched, rumbling, mid-diastolic murmur heard loudest over the apex.

Aetiology

Rheumatic heart disease is the most common cause of mitral stenosis.
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Other rarer causes include\:
Congenital
Left atrial myxoma
Connective tissue disorders
Mucopolysaccharidosis

Clinical features

Typical features of a mitral stenosis murmur include\:
Low-pitched, rumbling mid-diastolic murmur with an opening click (click heard in mid-diastole when the mitral valve opens)
Murmur is heard loudest over the apex
Loudest in left lateral decubitus position on expiration
Other clinical features of mitral stenosis may include\:
A low-volume pulse which may be irregularly, irregular (atrial is common in mitral stenosis)
Loud
A malar

Mitral valve prolapse

A mitral valve prolapse occurs when the mitral valve lea
Mitral valve prolapse is associated with a combination of a mid-systolic click and mid to late-systolic murmur.

Aetiology

Mitral valve prolapse is the most common valvular abnormality with a prevalence of approximately 5%.
The exact underlying cause of mitral valve prolapse is unknown. Primary mitral valve prolapse is caused by myxomatous
degeneration of the mitral valve and is associated with connective tissue diseases. Secondary mitral valve prolapse occurs
when a 'normal' valve prolapses.

Clinical features

Typical features of a mitral valve prolapse murmur include\:
Mid-systolic click (prolapse of the mitral valve into the left atrium)
Followed by a mid or late-systolic murmur
Heard loudest at the apex
Loudest in expiration

Tricuspid regurgitation

Tricuspid regurgitation occurs when there is the back
ventricular systole. This causes an increase in right atrial pressure and elevated venous pressures.
Tricuspid regurgitation is associated with a pansystolic murmur heard loudest over the tricuspid region.

Aetiology

Causes of tricuspid regurgitation include\:
Right ventricular dilatation (e.g. secondary to pulmonary stenosis or pulmonary hypertension)
Rheumatic fever
Infective endocarditis (intravenous drug users are at high risk of endocarditis a
Carcinoid syndrome
Congenital (e.g. atrial septal defect, Ebstein anomaly)
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Ebstein anomaly
The Ebstein anomaly (i.e. congenital isolated tricuspid regurgitation) is an abnormal attachment of tricuspid valve lea
which causes the tricuspid valve to displace downwards into the right ventricle.

Clinical features

Typical features of a tricuspid regurgitation murmur include\:
Pansystolic murmur
Heard loudest over the tricuspid region
Loudest during inspiration
Other clinical features of tricuspid regurgitation may include\:
Large ‘v-waves’ visible in the jugular veins\: caused by the right atrial
Visible/palpable hepatic pulsations
Signs of right-sided heart failure\: right ventricular heave, peripheral oedema, hepatomegaly, ascites

Pulmonary stenosis

Pulmonary stenosis (PS) refers to the narrowing of the pulmonary valve. It is commonly associated with other congenital heart
defects.

Aetiology

Causes of pulmonary stenosis include\:
Congenital\: Turner’s, Noonan’s and Williams syndromes. Tetralogy of Fallot (pulmonary stenosis, right ventricular hypertrophy,
ventricular septal defect and an overriding aorta).
Rheumatic fever
Carcinoid syndrome

Clinical features

Typical features of a pulmonary stenosis murmur include\:
Ejection systolic murmur heard loudest over pulmonary area
Loudest during inspiration
Radiates to left shoulder/left infraclavicular region
In severe pulmonary stenosis, the murmur is longer and may obscure the sound of A2
Other clinical features of pulmonary stenosis may include\:
Prominent ‘a waves’ in the jugular veins
Widely split S2\: blood from the ventricles takes longer to pass through a narrow pulmonary valve, so pulmonary valve
closure occurs much later than aortic valve closure
P2 may be soft and inaudible
Right ventricular dilatation can lead to a right ventricular heave, tricuspid regurgitation and peripheral signs of right-sided
heart failure (e.g. peripheral oedema, ascites etc)

Pulmonary regurgitation

Pulmonary regurgitation (PR) occurs when there is back
ventricular diastole. Pulmonary regurgitation is rare.

Aetiology

Causes of pulmonary regurgitation include\:
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Pulmonary hypertension
Infective endocarditis
Congenital valvular heart disease

Clinical features

Pulmonary regurgitation is usually asymptomatic.
Typical features of a pulmonary regurgitation murmur include\:
Early decrescendo murmur heard loudest over the left sternal edge
Loudest during inspiration
Usually due to pulmonary hypertension\: known as a Graham Steell murmur when associated with mitral stenosis

Tricuspid stenosis

Tricuspid stenosis (TS) refers to narrowing of the tricuspid valve.
Tricuspid stenosis is associated with a soft diastolic murmur heard loudest at 3rd - 4th intercostal space at the left sternal
edge

Aetiology

Causes of tricuspid stenosis include\:
Rheumatic fever (most common)
Congenital disease
Infective endocarditis

Clinical features

Typical features of a tricuspid stenosis murmur include\:
Mid-diastolic murmur (rarely audible)
Loudest at 3rd - 4th intercostal space at the left sternal edge
Loudest during inspiration
Other clinical features of tricuspid stenosis may include\:
Raised JVP with giant ‘a waves’
Peripheral oedema, ascites

Summary

Table 2. Overview of di
Lesion Cardiac cycle Character Breathing Location Radiation
Aortic stenosis Systolic
Ejection
systolic
Expiration
2nd intercostal space right
sternal edge
Systolic
Ejection
systolic
Inspiration
2nd intercostal space left
sternal edge
Systolic Pansystolic Expiration Apex Axilla
Carotid arteries
Left shoulder/infra-
clavicular
Pulmonary
stenosis
Mitral
regurgitation
Tricuspid
regurgitation
Mitral valve
prolapse
Systolic Pansystolic Inspiration Left sternal edge
Mid systolic +
opening click
Expiration Apex
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Aortic
regurgitation
Early diastolic Decrescendo Expiration
Pulmonary
regurgitation
Early diastolic Decrescendo Inspiration
Left sternal edge (or 2nd
intercostal space right sternal
edge)
2nd intercostal space left
sternal edge
Left sternal edge
Mitral stenosis
Tricuspid stenosis
Mid/late
diastolic
Mid/late
diastolic
Expiration Apex
Inspiration Left sternal edge
Source\: geekymedics.com
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