Dilated Cardiomyopathy (Enlarged Heart)
Dilated cardiomyopathy (DCMO) is a heart condition, which usually presents between age 20 to 60[i],[ii]. Although no definitive statistics, it is thought to affect approximately 1 in every 2500 people[iii] or 6.0 per 100 000 per year[iv].
What is dilated cardiomyopathy?
DCMO is a condition where the main pumping chamber of the heart known as the Left ventricle becomes stretched and enlarged, impairing its ability to function optimally1,2,3. This may ultimately cause the other three heart chambers to enlarge as well, and eventually results in heart failure2.
What are the symptoms?
People with DCMO often present with signs and symptoms of heart failure including1,2,3:
- Fatigue / tiredness
- Dizziness or light headedness and possibly fainting
- Dyspnoea (shortness of breath), especially when lying down. This may be a result of fluid build up in the lungs.
- Difficulty exercising/ exercise intolerance
- Swelling of the lower legs
- Swelling of the abdomen due to ascites (fluid build up)
- Weight gain
- Chest pain, usually due to reduced oxygen supply to the heart
- Palpitations caused by arrhythmias (disruption to heart rhythm)
- Heart murmurs (abnormal heart sounds)
- Genetic (approximately 30 % of DCMO cases), 50 % chance of inheriting it from an infected parent.
- Coronary artery disease
- Hypertension (high blood pressure)
- Alcohol, especially in association with a poor diet
- Certain cancer medications
- Drug abuse especially cocaine
- Infections (bacterial, viral, fungal and parasite)
- Exposure to toxins such as lead, mercury or cobalt
- Complications from late pregnancy
- Auto-immune diseases.
- Pregnancy (Peripartum) – often develops during or within 3 months of birth.
How is dilated cardiomyopathy diagnosed?
When the diagnosis of DCMO is suspected, the first imaging modality is usually Chest X-Ray. The Chest X-Ray will be able to detect the enlargement of the Left ventricle and atrium with possible pulmonary edema5. There may be an associated pleural effusion which can also be seen on the X-Ray5.
The next step would be to go for an echocardiogram/ultrasound of the heart. Ultrasound studies of the heart is an excellent imaging modality that gives valuable information of the size of the heart, how well it is functioning, how well the valves are opening and closing and whether there are any growths or blood clots.
With DCMO the severity of the disease can be determined on ultrasound by determining the size of the chamber and the extent of the thinning of the walls5. Ultrasound is especially useful in determining the ejection fraction of the heart, which tells us whether the heart is pumping adequately to supply the body3. The ejection fraction is calculated by measuring the percentage of blood pumped out by the heart per contraction and the normal range is between 45 and 60 %3. Reduction in the ejection fraction is what leads to fatigue and other symptoms.
Sometimes your doctor may need a cardiac / heart MRI for further information about the extent of the disease.
Other tests that may be useful in assessing DCMO may include: blood tests, an electrocardiogram (ECG) or an exercise stress test[i]
What is the treatment for dilated cardiomyopathy?
Treatment is mainly aimed at managing the symptoms and reducing the risk of complications. Ongoing monitoring and treatment are important3. Medications may be given to reduce the swelling (diuretics), reduce the pressure on the heart (e.g. ACE inhibitors), reducing the rate of heart contractions (Beta-blockers), blood thinners to reduce the risk of clots and blood vessel dilators to reduce the blood pressure3. Pacemakers and implantable cardioverters/defibrillators may be inserted to regulate the heart rhythm and detect and reverse dangerous arrhythmias3,6. Surgery may also be necessary depending on the severity of the condition3,6.
Changes in lifestyle will also assist in managing DCMO, these include minimizing alcohol, a healthy diet, minimizing salt, quitting smoking and reducing caffeine intake3,6. Moderate exercise is also advised3.
What are the possible complications?
Complications that may result from DCMO include1,3:
- Heart failure
- Heart valve regurgitations
- Heart block (slowing of the electrical activity)
- Edema (swelling of the legs and fluid build up in the lungs)
- Arrhythmias (abnormal heart rhythms)
- Sudden cardiac arrest / death
- Blood clots
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- Mayo Clinic[Internet]. Dilated cardiomyopathy. Mayo Foundation for Medical Education and Research (MFMER) [Update 2018 March 09, cited 2019 December 12]. Available from https://www.mayoclinic.org/diseases-conditions/dilated-cardiomyopathy/symptoms-causes/syc-20353149
- American Heart Association [Internet]. Dilated Cardiomyopathy (DCM). American Heart Association, Inc. [Updated 2016 March 31, Cited 2019 December 12]. Available from
- https://www.heart.org/en/health-topics/cardiomyopathy/what-is-cardiomyopathy-in-adults/dilated-cardiomyopathy-dcmCardiomyopathy UK [Internet]. Dilated Cardiomyopathy DCM. Cardiomyopathy UK [Updated 2017 August, Cited 2019 December 12]. Available from https://www.cardiomyopathy.org/dilated-cardiomyopathy/intro
- Kaddoura S. Echo Made Easy E-Book. Elsevier Health Sciences; 2016 Jul 5.
- Radiopaedia [Internet]. Dilated Cardiomyopathy. Radiopaedia.org. [Cited 2019 December 12]. Available from https://radiopaedia.org/articles/dilated-cardiomyopathy?lang=us
- WebMD [Internet]. Heart disease and Dilated Cardiomyopathy. WebMD LLC. [Updated 2018 September 05, Cited 2019 December 12]. Available from www.webmd.com/heart-disease/guide/dilated-cardiomyopathy#1