Dilated Cardiomyopathy Explained: Causes, Symptoms and Treatment
- MedReport Foundation
- 1 day ago
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Introduction
Dilated cardiomyopathy (DCM) is a heart condition in which the heart muscle becomes
enlarged and weakened, making it harder to pump blood around the body (1). This can cause symptoms such as tiredness and breathlessness, although some people may not notice anything at first (1,2). DCM can occur at any age, but it is most often seen in adults between 20 and 60 years old (1). As symptoms may develop slowly, many people are only diagnosed once the heart has already become significantly weakened (1).
What Happens in the Heart?
In DCM, the heart’s main pumping chambers (the ventricles) stretch and become thinner,
reducing the heart’s ability to pump blood effectively. Over time, the enlarged heart can also
place strain on the heart valves, causing them to leak, and irregular heart rhythms may
develop (1). At first, the body tries to cope by increasing heart rate and releasing hormones to maintain blood flow. But over time, these changes become harmful and further weaken the heart. Under the microscope, the heart muscle often shows scarring (fibrosis) and structural damage (1).
Causes of Dilated Cardiomyopathy
Non-Genetic Causes
In many cases, DCM develops due to external factors or health issues that damage the heart
over time. Common causes include viral infections that inflame the heart muscle (called
myocarditis), long-term heavy alcohol use, certain chemotherapy drugs, hormonal disorders,
pregnancy-related cardiomyopathy, and autoimmune or inflammatory conditions (1,2).
Some conditions can look like DCM, such as stress-induced cardiomyopathy or heart disease caused by blocked arteries, but these are considered separate conditions (1).
Genetic Causes
Many DCM cases are genetic, with around one-third recognised as inherited (2). Changes in
over 50 genes have been linked to DCM, most often passed down in an autosomal dominant
pattern, meaning only one altered gene copy from a parent is needed to cause disease (2).
These genes help keep heart muscle cells strong and working properly. When they do not
function correctly, the heart muscle gradually weakens and struggles to pump effectively.
Even without family history, new genetic changes (de novo changes) can sometimes cause
DCM in someone for the first time (2).
Symptoms
Symptoms of DCM usually develop gradually as the heart’s pumping ability declines. Common symptoms include:
Shortness of breath, especially during exercise or when lying down (1)
Fatigue and reduced ability to exercise (1)
Swelling of the legs, ankles, or abdomen (1)
Waking at night feeling breathless (1)
Some people may also experience palpitations (fluttering heartbeat), dizziness, or chest
discomfort. Doctors may detect signs of heart failure, such as fluid in the lungs, swelling, or
abnormal heart sounds (1). In some cases, additional features such as muscle weakness or hearing problems may point to a genetic cause (2).
Diagnosis
DCM is diagnosed after ruling out other heart problems (2). Doctors start with a full medical
history, a physical check, and tests to identify any fixable causes such as thyroid disease,
infections, or alcohol use (1).
The most important test is an echocardiogram (heart ultrasound), which shows if the heart
chambers are enlarged and how well the heart pumps blood (1). Other tests may include:
Electrocardiogram (ECG) to assess heart rhythm (1)
Chest X-ray to detect heart enlargement or fluid in the lungs (1)
Blood tests, including BNP levels that rise with heart strain (1)
Coronary angiography to rule out blocked arteries (1)
Genetic testing may be recommended, particularly in younger patients or those with a family
history, as many DCM cases are linked to gene changes (2).
Treatment and Management
Treatment aims to improve symptoms, slow disease progression, and reduce complications.
Most patients are managed using standard heart failure treatments alongside lifestyle changes (1).
Medications
Common medications include:
Diuretics to remove excess fluid and reduce swelling (1)
ACE inhibitors or Angiotensin II receptor blockers (ARBs) to reduce strain on the heart (1)
Beta-blockers to improve heart function and reduce arrhythmias (irregular rhythms) (1)
Mineralocorticoid receptor antagonists for more advanced cases (1)
Additional medications may be used depending on disease severity (1).
Devices and Advanced Therapies
For patients at higher risk, devices such as implantable cardioverter-defibrillators (ICDs) can
prevent life-threatening arrhythmias by shocking the heart back to normal rhythm, or cardiac
resynchronisation therapy (CRT) helps the heart pump more efficiently (1).
In severe cases where symptoms continue despite treatment, options such as left ventricular
assist devices or heart transplantation may be considered (1).
Lifestyle Changes
Daily habits play a key role in managing DCM. Patients are advised to:
Reduce salt and fluid intake
Avoid alcohol and recreational drugs
Take medications as prescribed
Attend all check-up appointments
Cardiac rehabilitation programmes, which include supervised exercise and education, can
significantly improve symptoms and quality of life (1).
Conclusion
DCM is a serious heart condition where the heart enlarges and weakens, making it harder to
effectively pump blood around the body. While the exact cause is not always clear, both
genetic and non-genetic factors often play a role.
The good news is that early diagnosis, appropriate treatment, and simple lifestyle changes can significantly improve outcomes. Ongoing advances in medical therapy, cardiac devices, and genetic research are continuing to improve care and offer new hope for patients and families living with DCM.
References
1. Mahmaljy H, Yelamanchili VS, Singhal M. Dilated cardiomyopathy [Internet].
PubMed. Treasure Island (FL): StatPearls Publishing; 2023. Available from:
2. Wang S, Zhang Z, He J, Liu J, Guo X, Chu H, et al. Comprehensive review on gene
mutations contributing to dilated cardiomyopathy. Frontiers in cardiovascular
medicine [Internet]. 2023 Dec 1;10. Available from:
3. Cleveland Clinic. Dilated cardiomyopathy [Internet]. Cleveland Clinic. 2022.
Available from: https://my.clevelandclinic.org/health/diseases/16932-dilated-
cardiomyopathy (Source for figure)
