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Cardiomyopathy is a condition in which the structure and function of the heart muscle is altered. As the heart muscle weakens, the heart finds it more difficult to contract and relax and less blood is pumped to the lungs and the rest of the body. This can affect both the left and right ventricles. Eventually, if left untreated, the heart dilates and heart failure ensues.

The are many causes of dilated cardiomyopathy. In a proportion, dilated cardiomyopathy can run in families (‘familial dilated cardiomyopathy’). The cause of familial cardiomyopathy is a genetic defect that cannot be corrected. In such cases, the condition develops between the ages of 20 and 60. In around 50% of cases of DCM, no cause can be found and the condition is then termed ‘idiopathic’ dilated cardiomyopathy.

Symptoms occur when heart failure ensues. They include:

Breathlessness: This can be due to accumulation of fluid in the lungs (pulmonary oedema), but can also occur in its absence. When there is fluid in the lungs, a cough or wheezing can occur.

Fluid retention (oedema): In heart failure, the kidneys respond by promoting the retention of fluid. This collects in the most dependent parts of the body, ie. the legs. Passing urine at night, breathlessness on lying down (orthopnoea) and waking up at night gasping for air (paroxysmal nocturnal dyspnoea) can also occur.

Fatigue: this results from a reduction in the blood suppy to all parts of the body.

Palpitations: As the heart tries to compensate for the reduction in blood supply, it speeds up and this is felt as rapid or irregular heartbeats.

Doctors can diagnose heart failure by taking a history and examining the patient. Often, investigations are needed to explore what has caused heart failure and how best to treat it.


ECG (heart trace): Although the ECG does not confirm the diagnosis of heart failure, it is more than likely abnormal in patients with the condition. It can reveal previous heart attacks and disorders of heart rhythm.

NT pro-natriuretic peptide (NT pro-BNP) blood test. This hormone is secreted from the heart when it stretches. A rased NT pro-BNP makes heart failure more likely, but it does not confirm the diagnosis. A low BNP test makes heart failure unlikely. Any condition that stretches the muscle of the heart, such as atrial fibrillation and valve disease, leads to elevations in NT pro-BNP. If you have a raised NT pro-BNP, do not immediately assume that you have heart failure.

Chest X-ray: A chest X-ray can give an approximation of the size of the heart and can show whether there is fluid in the lungs (pulmonary oedema and pleural effusions). It does not, however, provide information of heart function.

• Echocardiogram: provides a very comprehensive assessment of the heart structures and function. It should be performed for the diagnosis and monitoring of heart failure.

Cardiac MRI scan: This specialised scan provides very accurate information on heart function and the causes of heart failure.

Cardiac catheterisation: This may required to assess the cause of heart failure.

​Family screening
Between 30% and 50% of people with idiopathic dilated cardiomyopathy have inherited a genetic mutation for the disease. Some of these mutations can be identified with blood testing. In the majority of cases, however, genetic testing is unfruitful. This is because there many genes to consider and even if you carry the gene, that does not mean you are going to develop the disease. Conversely, absence of a genetic defect does not necessarily mean you are not going to develop the disease.

Screening tests are geared towards monitoring of cardiac function and structure with an echocardiogram and/or a cardiac MRI scan.

This is geared towards treating the underlying cause and its effects on cardiac function.  If the cause of the cardiomyopathy is identified, this may involve avoiding exposure to toxins, such as alcohol and cocaine. The treatment of the function of the heart is as for heart failure. 

Cardiomyopathy links

The Cardiomyopathy Association:​Cardiomyopathy Association information leaflet

BHF booklet:

Translated information booklets in Punjabi, Urdu, Hindi and Gujarati:

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