Aortic stenosis

Aortic stenosis
Aortic stenosis (AS) refers to a tightening of the aortic valve at the origin of the aorta.

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:

Calcification of the aortic valves: this is the most common cause of AS in developed countries, typically occurring in elderly 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)

Mitral regurgitation

Mitral regurgitation (MR) occurs when there is backflow (regurgitation) of blood from the left ventricle into the left atria (through the mitral valve) during ventricular systole.

Mitral regurgitation is associated with a pansystolic murmur heart 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 mitral area
Radiation of the murmur to the axilla
Heard loudest using the bell of the stethoscope
Loudest on expiration in the left lateral decubitus position
Other clinical features may include:

Displaced, hyperdynamic apex beat

Aortic regurgitation

Aortic regurgitation (AR) occurs when there is backflow of blood from the aorta into the left ventricle during ventricular 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 affecting the valve itself, or due to dilatation of the aortic root.

Diseases affecting the valve include:

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)
Aortitis
Typical clinical features
Typical features of an aortic regurgitation murmur include:

Decrescendo early diastolic murmur
Heard loudest at left sternal edge (the direction that the turbulent blood flows) sometimes heard loudest over the aortic 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.

Mitral stenosis
Mitral stenosis (MS) is narrowing of the mitral valve, which results in decreased filling of the left ventricle during systole 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.

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 fibrillation is common in mitral stenosis)
Loud first heart sound with tapping apex beat (due to a palpable closing of the mitral valve)
A malar flush (plum-red discolouration of the cheeks)

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