Mitral Regurgitation

Question 1

… … refers to an incompetence of the valve that may occur due to abnormalities to the valve leaflets, subvalvular apparatus or left ventricle.

Answer 1

Mitral regurgitation refers to an incompetence of the valve that may occur due to abnormalities to the valve leaflets, subvalvular apparatus or left ventricle.

Question 2

Regurgitation refers to a ‘leaking’ of blood through the valve during ventricular systole. It can be classified as primary or secondary:

Answer 2

Primary: refers to pathology affecting components of the valve itself. Degenerative disease is the most common cause.
Secondary: refers to regurgitation as a result of changes to left ventricular geometry. This results in distortion of the subvalvular apparatus and valve leaflets. Dilated and ischaemic cardiomyopathies are the most common cause.

Question 3

… is the second most common indication for valvular surgery (the most common being aortic stenosis).

Answer 3

It may also be classified into acute and chronic disease based on the speed of onset and severity of regurgitation. Mitral regurgitation is the second most common indication for valvular surgery (the most common being aortic stenosis).

Question 4

The … valve is termed (somewhat erroneously) a bicuspid valve and sits between the left atrium and ventricle.

Answer 4

The mitral valve is termed (somewhat erroneously) a bicuspid valve and sits between the left atrium and ventricle.

Question 5

Primary MR: degenerative valve disease is the most common cause. Other causes include: (4)

Answer 5

Primary MR: degenerative valve disease is the most common cause. Other causes include:

Infective endocarditis
Rheumatic heart disease
Congenital anomalies
Medications (e.g. ergotamine, bromocriptine, pergolide)

Question 6

Secondary MR: ischaemic MR may result in chronic MR following a myocardial infarction (more commonly than acute ischaemic MR). The ischaemic insult leads to left ventriclar remodelling and dysfunction impairing the valves ability to close. Other causes include …

Answer 6

Secondary MR: ischaemic MR may result in chronic MR following a myocardial infarction (more commonly than acute ischaemic MR). The ischaemic insult leads to left ventriclar remodelling and dysfunction impairing the valves ability to close. Other causes include cardiomyopathy (dilated and hypertrophic).

Question 7

MR results in a backflow of blood during ventricular systole from the left ventricle into the left atrium. This … the ejection fraction as part is flowing backwards and … the atrial pressure.

Answer 7

MR results in a backflow of blood during ventricular systole from the left ventricle into the left atrium. This reduces the ejection fraction as part is flowing backwards and raises the atrial pressure.

Question 8

In chronic MR there is gradual worsening of the regurgitant fraction that initially allows for compensatory mechanisms to occur. Eventually failure may result and the patient enters a decompensated state:

Answer 8

Compensated state: in the setting of mitral regurgitation the left ventricle and atrium dilate. The compliant and dilated left ventricle undergoes eccentric hypertrophy and is able to maintain a larger stroke volume and as such ejection fraction. The compliant and dilated left atrium prevents rises in atrial and therefore pulmonary pressures.
Decompensated state: eventually such changes cannot maintain normal cardiac function and the remodelling becomes increasingly pathological. The heart fails, ejection fraction falls and pulmonary pressures rise.

Question 9

The clinical features of MR include the signs and symptoms of heart failure and a … murmur.

Answer 9

The clinical features of MR include the signs and symptoms of heart failure and a pansystolic murmur.

Question 10

The clinical features of … include the signs and symptoms of heart failure and a pansystolic murmur.

Answer 10

The clinical features of MR include the signs and symptoms of heart failure and a pansystolic murmur.

Question 11

Acute MR: characterised by the rapid development of heart failure with inadequate cardiac output and flash … … Patients may be shocked and breathless, the condition is potentially life-threatening, and can necessitate emergency surgery.

Answer 11

Acute MR: characterised by the rapid development of heart failure with inadequate cardiac output and flash pulmonary oedema. Patients may be shocked and breathless, the condition is potentially life-threatening, and can necessitate emergency surgery.

Question 12

Chronic MR: may be asymptomatic for many years until heart failure results in symptoms developing. Symptoms tend to involve dyspnoea and orthopnoea that results from … …. Fatigue and malaise are common. As right-sided heart failure develops patients may notice swelling of their ankles (peripheral oedema).

Answer 12

Chronic MR: may be asymptomatic for many years until heart failure results in symptoms developing. Symptoms tend to involve dyspnoea and orthopnoea that results from pulmonary hypertension. Fatigue and malaise are common. As right-sided heart failure develops patients may notice swelling of their ankles (peripheral oedema).

Question 13

As right-sided heart failure develops patients may notice …

Answer 13

As right-sided heart failure develops patients may notice swelling of their ankles (peripheral oedema).

Question 14

Signs of MR - palpation

Answer 14

Palpation: the apex beat may be displaced laterally. A systolic thrill may be felt in severe disease.

Question 15

Signs of MR - murmur

Answer 15

Murmur: a pansystolic murmur is characteristic.

Question 16

Signs of MR - heart sounds

Answer 16

S1 (first heart sound) may be soft due to incomplete closure. An additional heart sound, S3, may be heard caused by rapid filling of a dilated ventricle.

Question 17

Signs of MR - heart failure signs

Answer 17

auscultation may note bi-basal crackles and examination demonstrate peripheral oedema.

Question 18

… allows for the confirmation of an incompetent valve, assessment of the severity and identification the underlying cause.

Answer 18

Echocardiogram allows for the confirmation of an incompetent valve, assessment of the severity and identification the underlying cause.

Question 19

In chronic MR evidence of left atrial and ventricular enlargement is often seen. In acute MR cardiomegaly is normally absent (unless there was pre-existing pathology) and signs of pulmonary oedema are seen.

On the CXR … .. enlargement can be seen with the tell-tale sign of a ‘… … heart border’ cause by the large …

Answer 19

In chronic MR evidence of left atrial and ventricular enlargement is often seen. In acute MR cardiomegaly is normally absent (unless there was pre-existing pathology) and signs of pulmonary oedema are seen. On the CXR left atrial enlargement can be seen with the tell-tale sign of a ‘double right heart border’ cause by the large left atrium.

Question 20

ECG - MR

Answer 20

In acute MR the ECG may be entirely normal or reflect a recent myocardial infarction. In chronic MR changes can include p-mitrale - a broad, notched p-wave with a negative component in V1 - (reflecting left atrial enlargement) and signs of left ventricular hypertrophy. Arrhythmia’s, most commonly atrial fibrillation, are sometimes present.

Question 21

Echo - MR

Answer 21

Echo is the diagnostic modality of choice. Allows visualisation of the incompetent valve and can confirm the underlying aetiology. Left atrial and ventricular enlargement may be seen in chronic MR.

Question 22

Other investigations for MR

Answer 22

Exercise testing: cardiopulmonary exercise testing may be used to assess a patients overall functional capacity. Exercise echocardiography is used to demonstrate changes in MR during exercise.
Cardiac MRI: may be used when echocardiogram is inadequate.
Cardiac catheterisation: an invasive investigation typically used for evaluation of the coronary vessels prior to valvular surgery. Right sided catheterisation can be used to confirm pulmonary hypertension.

Question 23

Patients with acute MR are normally profoundly unwell - the condition characterised by shock and flash … … Management follows two stages:

Answer 23

Patients with acute MR are normally profoundly unwell - the condition characterised by shock and flash pulmonary oedema. Management follows two stages:

Medical stabilisation: The aim is to stabilise the patient and allow for pre-operative optimisation. Sodium nitroprusside can be used to reduce afterload and thereby reduce MR. Patients with hypotension may require inotropic agents and an intra-aortic balloon pump.
Surgery: Timing of surgery depends on the patients clinical state and the underlying aetiology. In infective endocarditis and chordal rupture, repair is generally preferred. When secondary to papillary muscle rupture, replacement is typically required.

Question 24

Patients with acute MR are normally profoundly unwell - the condition characterised by shock and flash pulmonary oedema. Management follows two stages:

Answer 24

Medical stabilisation: The aim is to stabilise the patient and allow for pre-operative optimisation. Sodium nitroprusside can be used to reduce afterload and thereby reduce MR. Patients with hypotension may require inotropic agents and an intra-aortic balloon pump.
Surgery: Timing of surgery depends on the patients clinical state and the underlying aetiology. In infective endocarditis and chordal rupture, repair is generally preferred. When secondary to papillary muscle rupture, replacement is typically required.

Question 25

Chronic MR management

Answer 25

Medical therapy: In patients with chronic MR and heart failure, ACE inhibitors, beta-blockers and spironolactone may all be considered. Cardiac resynchronisation therapy (CRT) is used when appropriate.
Surgical therapy: Surgery is considered in symptomatic patients with a LVEF > 30%. It is also considered in other patients (both symptomatic and asymptomatic) based on a complicated set of criteria. Other surgical measures include ventricular assist devices, cardiac restraint devices and heart transplantation.

Question 26

Surgery is considered in symptomatic patients with a LVEF > …% with chronic MR

Answer 26

Surgery is considered in symptomatic patients with a LVEF > 30% with chronic MR

Question 27

In patients with chronic MR and heart failure, ACE inhibitors, beta-blockers and spironolactone may all be considered
…. is used when appropriate.

Answer 27

In patients with chronic MR and heart failure, ACE inhibitors, beta-blockers and spironolactone may all be considered. Cardiac resynchronisation therapy (CRT) is used when appropriate.

Question 28

Managing secondary MR?

Answer 28

In secondary MR there is less conclusive evidence showing improved survival following mitral valve intervention.

Secondary MR is associated with increased mortality though at present there is less evidence showing surgical intervention improves outcomes. The management should be guided by MDT with key input from both heart failure and electrophysiology specialists. Medical therapy should follow heart failure management. CRT should be considered when appropriate.

Question 29

The indications for surgery are complex and in some cases have a relatively limited evidence base. In patients undergoing CABG with LVEF > …% with severe secondary MR, it should be considered. It is also discussed with patients with ongoing symptoms despite optimal medical therapy (including CRT if indicated).

Answer 29

The indications for surgery are complex and in some cases have a relatively limited evidence base. In patients undergoing CABG with LVEF > 30% with severe secondary MR, it should be considered. It is also discussed with patients with ongoing symptoms despite optimal medical therapy (including CRT if indicated).