Written by Dimitrios Vrachatis, Specialist Cardiologist, PhD, National and Kapodistrian University of Athens.
What is dilated cardiomyopathy?
Dilated cardiomyopathy is enlargement of the internal dimensions of the left or right ventricle, together with reduced systolic function, in the absence of other conditions that could explain these findings, such as high blood pressure, valvular heart disease or coronary artery disease. It is the most common non-ischaemic cardiomyopathy.
What causes it?
Its causes are broadly divided into genetic and non-genetic. In a large number of patients, no specific cause is identified (idiopathic). In other cases, causes include:
- Infectious myocarditis caused by viruses such as HIV, bacteria such as Lyme disease, or parasites such as Trypanosoma cruzi.
- Autoimmune myocarditis.
- Peripartum cardiomyopathy.
- Alcohol abuse.
- Cocaine, amphetamine or ecstasy use.
- Certain cytostatic or psychiatric medicines.
- Beta-thalassaemia.
- Persistent chronic tachycardia.
- Endocrine disorders, including hyperthyroidism, hypothyroidism, Cushing’s disease, phaeochromocytoma and diabetes mellitus.
In some cases it is an inherited disorder, usually with an autosomal dominant pattern.
Who can be affected?
It may affect people of all ages, but is more common in middle-aged people and in men.
Which examinations are needed?
The initial examination is an echocardiogram. More extensive assessment, including Holter ECG, coronary angiography and cardiac MRI, is usually needed both to exclude other conditions and to determine the precise cause.
What are the symptoms?
Dilated cardiomyopathy usually presents as heart failure, with its associated signs and symptoms — fatigue, shortness of breath, leg swelling, palpitations and others. It may develop suddenly or gradually. Treatment is directed accordingly.
What is the treatment?
Treatment is guided by any trigger that is identified and by the signs and symptoms of heart failure, following the relevant general guidance. The most advanced treatment is heart transplantation, provided that specific criteria and requirements are met.
Should relatives be screened?
All first-degree relatives of a person with dilated cardiomyopathy should be monitored with an electrocardiogram and an echocardiogram. Genetic testing is required only when there are specific indications.
Dilated cardiomyopathy and exercise
If symptoms are present, moderate- or high-intensity exercise should be avoided.
People without symptoms may take part in low- to moderate-intensity exercise, regardless of left ventricular ejection fraction, provided that assessment has confirmed:
- No arrhythmia burden at rest, using Holter monitoring.
- No arrhythmia burden during exercise, using an exercise stress test.
Higher-intensity activity requires several additional conditions to be met and further extensive assessment.
People who carry a gene mutation causing dilated cardiomyopathy but have no manifestations of disease (phenotypically healthy) may participate in sporting activities, with exceptions for certain particularly aggressive mutations, such as lamin A/C or filamin C.
Genetic counselling and counselling about a possible pregnancy
Because cardiomyopathies are rare and knowledge in this field is evolving rapidly, counselling about genetic testing for the individual or their relatives, and about a possible future pregnancy, is provided at specialised centres.