Heart murmur

A heart murmur is the sound that is heard with a stethoscope when there is turbulent blood flow through the heart. Turbulent blood flow through the heart is usually caused by abnormally function heart valves but can be caused by other conditions. Not all heart murmurs are caused by disease of the heart – some are quite normal and are termed ‘innocent heart murmurs’.

 

Symptoms

People with heart murmurs are often not aware of any symptoms and the murmur is only picked up incidentally when somebody listens (auscultates) the heart as part of a normal clinical examination. Symptoms that are attributable to heart murmurs include the following:

• Shortness of breath

• Palpitations (awareness of heart beat)

• Chest discomfort

• Dizziness (on exertion)

• Blackouts (on exertion)

• Swelling of the ankles and legs

 

Causes

There are a number of different causes of murmurs. These can be divided into problems that affect the heart valves, problems that affect the heart muscle and problems that affect the blood vessels.

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Heart valve abnormality

• Leaking valves – most commonly the mitral, aortic and tricuspid valves

• Narrowed valves – most commonly the aortic  and mitral valve

 

Heart muscle abnormality

• Abnormal thickening of the heart muscle – hypertrophic obstructive cardiomyopathy

• Abnormality in the heart muscle – ventricular septal or atrial septal defect

 

Abnormality in the blood vessels

• Coarctation of the aorta

• Patent ductus arteriosus

 

Investigations

The following investigations are usually required for investigation of a heart murmur:

• Ultrasound of the heart or echocardiogram is a test used to assess the structure and function of the heart

• ECG or electrocardiogram is an electrical reading of the heart that is performed by placing electrode stickers on the skin of the chest wall.

• Cardiac MRI can be performed to have a detailed assessment of the heart’s structure and function. 

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