Diseases of Heart Valves

Question 1

What causes valve regurgitation?

Answer 1

Regurgitation = valve fails to close properly and permits a jet of blood to flow back through to the chamber it was ejected from

Congenital
Acute rheumatic carditis
Chronic rheumatic carditis
Infective endocarditis
Valve ring dilatation (e.g. dilated cardiomyopathy)
Syphilitic aortitis
Traumatic valve rupture 
Senile degeneration
Damage to chordae and papillary muscles (e.g. MI)

Question 2

What causes valve stenosis?

Answer 2

Stenosis = narrowed valve that is difficult to open and exerts a pressure overload on the chamber trying to eject blood through it

Congenital
Rheumatic carditis
Senile degeneration

Question 3

What is mitral stenosis?

Answer 3

Mitral stenosis (MS) is the thickening of the mitral leaflets that may occur at the cusps, commissures
or chordal level, to cause an obstruction of blood flow from the left atrium to the left ventricle.

Question 4

What causes mitral stenosis?

Answer 4

The most common cause remains chronic rheumatic heart disease, which involves a sustained inflammatory reaction against the valve and valvular apparatus, due to antibody cross-reactivity to a streptococcal illness. Rarer causes include congenital disease, carcinoid, systemic lupus erythematosus (SLE) and mucopolysaccharidoses (glycoprotein deposits on cusps). Rheumatic heart disease originating in the UK is now exceptionally rare.

Question 5

What valve area is characteristic of mitral stenosis?

Answer 5

A normal mitral valve has a valve area of 4–6 cm2: MS is diagnosed when the valve area is ≤2cm2: It
is considered severe when ≤1cm2; symptoms are invariable and increased pulmonary pressures lead to pulmonary oedema, when heart rates increase, and pulmonary hypertension. Atrial fibrillation is invariable and increases thromboembolic stroke risk by 17×; anticoagulation is essential.

Question 6

What are the symptoms of mitral stenosis?

Answer 6

Dyspnoea with minimal activity
Haemoptysis
Dysphagia (due to left atrium enlargement)
Palpitations due to atrial fibrillation

Question 7

How might the chest radiograph look in mitral stenosis?

Answer 7

Left atrial or right ventricular enlargement
Splaying of subcarinal angle (>90°)
Pulmonary congestion or hypertension
Pulmonary haemosiderosis

Question 8

What signs on examination are associated with mitral stenosis?

Answer 8

Low pulse pressure
Soft first heart sound
Long diastolic murmur and apical thrill (rare)
Very early opening snap, ie closer to S2 (lost if valves immobile)
Right ventricular heave or loud P2
Pulmonary regurgitation (Graham Steell murmur)
Tricuspid regurgitation (due to right ventricular hypertrophy and dilatation)

Question 9

How is mitral stenosis treated?

Answer 9

Treatment can be percutaneous (balloon valvuloplasty) or surgical (limited mitral valvotomy – now rarely performed in developed nations – or open valve replacement).

Question 10

When is mitral balloon valvuloplasty considered in mitral stenosis?

Answer 10

Valvuloplasty using an Inoue balloon requires either a trans-septal or a retrograde approach, and is used only in suitable cases where echocardiography shows the following:
• The mitral leaflet tips and valvular chordae are not heavily thickened, distorted or calcified
• The mitral cusps are mobile at the base
• There is minimal or no mitral regurgitation
• There is no left atrial thrombus seen on TOE

Question 11

What are the main causes of mitral regurgitation?

Answer 11

Myxomatous degeneration
Functional, secondary to ventricular dilatation
Mitral valve prolapse
Ischaemic papillary muscle rupture
Congenital heart diseases
Collagen disorders
Rheumatic heart disease
Endocarditis

Question 12

What is the pathogenesis of mitral regurgitation?

Answer 12

Chronic mitral regurgitation causes gradual dilatation of the LA with little increase in pressure and therefore relatively few symptoms. Nevertheless, the LV dilates slowly and the left ventricular diastolic and left atrial pressures gradually increase as a result of chronic volume overload of the LV. In contrast, acute mitral regurgitation causes a rapid rise in left atrial pressure (because left atrial compliance is normal) and marked symptomatic deterioration

Question 13

What are the clinical features of mitral regurgitation?

Answer 13

Symptoms and signs depend on the underlying cause and how suddenly the regurgitation develops.

Chronic mitral regurgitation produces a symptom complex that is similar to that of mitral stenosis but sudden-onset mitral regurgitation usually presents with acute pulmonary oedema.

The regurgitant jet causes an apical systolic murmur, which radiates into the axilla and may be accompanied by a thrill. Increased forward flow through the mitral valve causes a loud third heart sound and even a short mid-diastolic murmur. The apex beat feels active and rocking due to left ventricular volume overload and is usually displaced to the left as a result of left ventricular dilatation.

Question 14

How is mitral regurgitation diagnosed?

Answer 14

Echocardiography is a pivotal investigation. The severity of regurgitation can be assessed by Doppler and information may also be gained on papillary muscle function and valve prolapse. An ECG should be performed and commonly shows AF, as a consequence of atrial dilatation. Cardiac catheterisation is indicated when surgery is being considered. During catheterisation, the severity of mitral regurgitation can be assessed by left ventriculography and by the size of the v (systolic) waves in the left atrial or pulmonary artery wedge pressure trace

Question 15

What findings suggest severe mitral regurgitation?

Answer 15

Small-volume pulse
Left ventricular enlargement due to overload
Presence of S3
Atrial fibrillation
Mid-diastolic flow murmur
Precordial thrill, signs of pulmonary hypertension or congestion (cardiac failure)

Question 16

How is mitral regurgitation managed?

Answer 16

Mitral regurgitation of moderate severity can be treated medically with diuretics and vasodilators. Digoxin and anticoagulants should be given if AF is present. If systemic hypertension is present, it should be treated with vasodilators such as ACE inhibitors or ARBs, since high afterload may worsen the degree of regurgitation. All patients should be reviewed at regular intervals, both clinically and by echocardiography. Worsening symptoms, progressive cardiomegaly or echocardiographic evidence of deteriorating left ventricular function are indications for mitral valve replacement or repair.

Question 17

Why is mitral regurgitation secondary to ventricular dilatation often made worse by surgical replacement of the valve?

Answer 17

If ventricular dilatation is the underlying cause of mitral regurgitation, then mitral valve repair or replacement may actually worsen ventricular function, as the ventricle can no longer empty into the low-pressure LA.

Question 18

What is mitral valve prolapse?

Answer 18

This condition occurs in 5% of the population and is commonly over-diagnosed (depending on the echocardiography criteria applied). The patients are usually female and may present with chest pains, palpitations or fatigue, although it is often detected incidentally in asymptomatic patients. Often there is myxomatous degeneration and redundant valve tissue due to deposition of acid mucopolysaccharide material

Question 19

How does mitral valve prolapse present?

Answer 19

Squatting increases the click and standing increases the murmur, but the condition may be diagnosed in the absence of the murmur by echocardiography. Mitral valve prolapse is usually eminently suitable for mitral valve repair, although this should be undertaken only if the severity of the regurgitation associated with the condition justifies it.

Question 20

What are the sequelae of mitral valve prolapse?

Answer 20

Embolic phenomena
Rupture of mitral valve chordae
Dysrhythmias with QT prolongation
Sudden death
Cardiac neurosis

Question 21

What conditions are associated with mitral valve prolapse?

Answer 21

Coronary artery disease
Polycystic kidney disease
Cardiomyopathy – dilated cardiomyopathy/HCM
Secundum ASD
WPW syndrome
PDA
Marfan’s syndrome
Pseudoxanthoma elasticum
Osteogenesis imperfecta
Myocarditis
SLE; polyarteritis nodosa
Muscular dystrophy
Left atrial myxoma

Question 22

What is the pathogenesis of aortic regurgitation?

Answer 22

Aortic regurgitation (AR) can occur due to disruption of the aortic valve or the aortic root. Either can occur acutely or chronically. Acute causes, including aortic dissection or valve rupture from endocarditis, present with acute decompensation and profound heart failure. Chronic causes allow time for the left ventricle to accommodate, with gradual enlargement of end-diastolic volumes.

Regurgitation of blood through the aortic value causes the LV to dilate as cardiac output increases to maintain the demands of the circulation. The stroke volume of the LV may eventually be doubled and the major arteries are then conspicuously pulsatile. As the disease progresses, left ventricular failure develops, leading to a rise in left ventricular end-diastolic pressure and pulmonary oedema.

Question 23

What are the causes of aortic regurgitation?

Answer 23

Valve inflammation:
• Chronic rheumatic
• Infective endocarditis
• Rheumatoid arthritis; SLE
• Hurler’s syndrome

Aortitis:
• Syphilis
• Ankylosing spondylitis
• Reiter’s syndrome
• Psoriatic arthropathy

Aortic dissection/trauma
Hypertension
Bicuspid aortic valve
Ruptured sinus of Valsalva’s aneurysm
VSD with prolapse of (right) coronary cusp

Disorders of collagen:
• Marfan’s syndrome (aortic aneurysm)
• Hurler’s syndrome
• Pseudoxanthoma elasticum

Question 24

What are the clinical features of aortic regurgitation?

Answer 24

Until the onset of breathlessness, the only symptom may be an awareness of the heart beat, particularly when lying on the left side, which results from the increased stroke volume. Paroxysmal nocturnal dyspnoea is sometimes the first symptom, and peripheral oedema or angina may occur. The characteristic murmur is best heard to the left of the sternum during held expiration; a thrill is rare. A systolic murmur due to the increased stroke volume is common and does not necessarily indicate stenosis. The regurgitant jet causes fluttering of the mitral valve and, if severe, causes partial closure of the anterior mitral leaflet, leading to functional mitral stenosis and a soft mid-diastolic (Austin Flint) murmur.

Question 25

How does aortic regurgitation present acutely?

Answer 25

Acute severe regurgitation may occur as the result of perforation of an aortic cusp in endocarditis. In this circumstance, there may be no time for compensatory left ventricular hypertrophy and dilatation to develop and the features of heart failure may predominate. The classical signs of aortic regurgitation in such patients may be masked by tachycardia and an abrupt rise in left ventricular end-diastolic pressure. The pulse pressure may also be normal or near-normal and the diastolic murmur may be short or even absent.