Murmurs

Question 1

What is a murmur?

Answer 1

A heart murmur is a blowing, whooshing, or rasping sound heard during a heartbeat.

Question 2

What causes a murmur?

Answer 2

Turbulent (rough) blood flow through the heart valves or near the heart

Question 3

What are the two subcategories of murmurs?

Answer 3

Systolic murmurs - arterial stenosis and mitral regurgitation

Diastolic murmurs - arterial regurgitation and mitral stenosis

Question 4

What is a systolic murmur?

Answer 4

This happens during a heart muscle contraction.

Systolic murmurs are divided into ejection murmurs (due to blood flow through a narrowed vessel or irregular valve) and regurgitant murmurs (backward blood flow into one of the chambers of the heart).

Question 5

What is a diastolic murmur?

Answer 5

This happens during heart muscle relaxation between beats.

Diastolic murmurs are due to a narrowing (stenosis) of the mitral or tricuspid valves, or regurgitation of the aortic or pulmonary valves.

Question 6

What are the four main types of murmurs to know?

Answer 6

Aortic stenosis
Mitral regurgitation
Mitral stenosis
Aortic regurgitation

Question 7

What is aortic stenosis?

Answer 7

Aortic stenosis is a narrowing of the aortic valve opening.

Question 8

What triad of symptoms is aortic stenosis associated with?

Answer 8

Heart failure
Syncope
Angina

Question 9

Signs on examination of aortic stenosis

Answer 9

Slow rising carotid pulse

Narrow pulse pressure

Heaving, non-displaced apex beat (can be displaced if there is left ventricular hypertrophy)

Ejection systolic murmur

Heard best at the second intercostal space on the right

Can be described as “harsh”

Transmitted well to the carotids

Soft S2 heart sound

Ejection click may be heard in some cases (early systolic)

Question 10

ECG findings in aortic stenosis

Answer 10

ECG in aortic stenosis can show evidence of left ventricular hypertrophy:

Increased QRS complex voltage
Left axis deviation
Poor R-wave progression

Note that the absence of these ECG findings does not preclude an AS diagnosis.

Question 11

What is mitral regurgitation?

Answer 11

The backflow of blood across the mitral valve during systole due to incompetence of the mitral valve.

Question 12

What causes acute mitral regurgitation?

Answer 12

Ischaemic MR - primarily due to papillary muscle rupture secondary to myocardial infarction.

Non-ischaemic MR - ruptured chordae tendineae due to any of a number of causes

Myxomatous disease (mitral prolapse)
Infective endocarditis
Rheumatic heart disease - acute or chronic
Trauma
Spontaneous rupture

Prosthetic valve MR -

Tissue valvelet rupture due to endocarditis, degeneration or calcification
Paravalvular regurgitation due to infection or suture rupture
Valve thrombus or infection causing impaired closure

Question 13

Is acute MR an emergency?

Answer 13

Acute mitral regurgitation is a cardiac emergency and may present with sudden onset pulmonary oedema, hypotension and cardiogenic shock.

Symptoms such as:

Shortness of breath
Exertional dyspnoea
Fatigue
Weakness

Question 14

Complications of MR

Answer 14

Heart failure
Thromboembolism secondary to AF
Haemoptysis secondary to pulmonary hypertension and symptoms of right heart failure are possible but less common than in mitral stenosis (MS).
Infective endocarditis and associated symptoms can also complicate M

Question 15

Examination findings in MR

Answer 15

Systolic murmur
Loudest at the apex
Pansystolic in nature
Radiates to the axilla
S1 may be quiet or absent

If patients are in decompensated heart failure:

Bilateral lung crepitations
Raised JVP
S3/S4
Peripheral/sacral oedema oedema

Question 16

What is mitral stenosis?

Answer 16

Impaired opening of the mitral valve affecting blood flow from the left atrium to ventricle.

Question 17

What is the most common cause of mitral stenosis?

Answer 17

Rheumatic heart disease. Streptococcal antigens secondary to bacterial infection cross-react with the valve tissue, causing damage.

Question 18

Signs of Mitral Stenosis

Answer 18

Mitral facies (malar flush) - cutaneous vasodilation due to carbon dioxide retention
Low volume pulse
Atrial fibrillation
Elevated JVP (prominent ‘a’ wave due to raised right atrial pressure, or absent ‘a’ wave in AF)
Tapping, non-displaced apex beat (palpable S1)
R ventricular heave (suggestive of pulmonary hypertension)
Inspiratory crepitations (pulmonary oedema) and other signs of right heart failure

Question 19

Cardiac auscultation findings in mitral stenosis

Answer 19

Loud S1 (becomes softer with increasing calcification)
Loud P2 with pulmonary hypertension (later stages S2 split)
Opening snap heard at apex (only with pliable valves)

Diastolic murmur -
Low pitched rumble, most prominent at apex
Loudest in expiration
Heard best with patient lying on left side
Heard best using stethoscope bell (low frequency)

Graham-Steell murmur (early diastolic murmur - only if pulmonary regurgitation present, secondary to pulmonary hypertension)

Question 20

What is aortic regurgitation?

Answer 20

Reverse flow of blood across the aortic valve in diastole due to the incompetence of the valve

Question 21

Acute causes of AR

Answer 21

Infective endocarditis and aortic dissection are the most common acute causes of AR.

Question 22

What are chronic causes of AR?

Answer 22

Calcific aortic valve disease (age related)
Myxomatous degeneration
Congenital disease e.g. bicuspid aortic valve
Rheumatic heart disease - most common cause in the developing world
Infective endocarditis
Rheumatic causes e.g. rheumatoid arthritis, antiphospholipid syndrome
Marfan’s syndrom