Cardiomyopathy occurs when the heart muscles become weak and/or stiff, making it harder for the heart to pump sufficient blood to supply the body’s needs. A common type of cardiomyopathy is dilated cardiomyopathy.
What happens when your heart muscle becomes stretched and thin, and cannot pump blood effectively?
Asst Prof Khoo Chun Yuan, Department of Cardiology, NHCS, shares with us the most common type of the heart muscle disease.
What is dilated cardiomyopathy? What are the symptoms?
Cardiomyopathy is a disease of the heart muscle. Due to various causes, the heart muscles become weak and/or stiff. This makes it harder for the heart to pump sufficient blood to supply the body’s needs. One of the most common types of cardiomyopathy is dilated cardiomyopathy. In this condition, the heart muscle becomes stretched and thin. This causes the heart pump chambers to become enlarged or dilated. The stretched and enlarged heart becomes weak and is unable to pump blood normally. When the heart is unable to pump enough blood for the body’s needs, it could result in heart failure.
Patients may develop decreased stamina, breathlessness, legs/ ankles/abdominal swelling, fatigue and sensation of abnormal heartbeat (palpitations).
Comparison of a normal heart (left) and heart with dilated cardiomyopathy (right).
What causes dilated cardiomyopathy?
Dilated cardiomyopathy mostly occurs in adults aged 20 to 60 years old. Common causes include excessive alcohol intake, genetic cause (whereby the condition is passed down in families), diabetes, obesity, thyroid disorders, heart rhythm abnormalities, virus infections causing heart muscle inflammation, and certain drugs used to treat cancer and complications during pregnancy. Often, the exact cause of dilated cardiomyopathy may not be known even after investigations.
How do we treat this condition?
It is important to start treatment as soon as possible, as dilated cardiomyopathy causes increased risks of death and hospitalisation. Studies have shown that on average, one out of five patients pass away from their weak heart function within a year of diagnosis1. Nearly half of all patients may get readmitted within a year.
Patients also usually experience distressing symptoms such as breathlessness, swollen legs and fatigue.
There are proven medications (guideline-directed heart failure therapy) that can make the patients feel better and reduce the risk of hospitalisations and death from this condition. Use of guideline directed heart failure medications in combination can potentially reduce risk of death by approximately 70%. It is important to take the medications regularly and as prescribed. In recent studies involving new classes of medications (such as SGLT-2 inhibitors2,3 and vericiguat4), there have been promising results showing the potential benefits to patients with dilated cardiomyopathy and heart failure. Treatment of underlying conditions such as heart rhythm abnormalities, thyroid disorders, cessation of alcohol and optimisation of diabetes, cholesterol and blood pressure control are also essential. Importantly, lifestyle measures such as reduced salt intake, management of fluid intake, smoking and alcohol cessation and prescribed physical activities also play an important role in the management of this condition.
If the heart pumping function remains severely depressed despite the above interventions, there is increased risk of abnormal heart rhythms occurring. The abnormal heart rhythm can lead to fainting episodes and/or sudden death. The cardiologist may discuss the options of implantation of specific devices such as implantable cardioverter defibrillator (ICD) and cardiac resynchronisation therapy (CRT). These devices may reduce risk of sudden death due to dangerous heart rhythm.
In the event that patient’s condition is worsening despite medications and lifestyle measures, heart transplant or implantation of an artificial heart pump (left ventricular assist device) may be an option after careful consideration.
While for some individuals, dilated cardiomyopathy may be genetic and not always preventable, it is important to maintain a healthy lifestyle such as balanced diet, adequate exercise, and avoidance of smoking and excessive alcohol so as to reduce risk of heart failure and occurrence of the condition. Good control of medical conditions such as diabetes, blood pressure and thyroid disorders is also essential.
1 Conrad N, Judge A, Canoy D et al. Temporal Trends and Patterns in Mortality After Incident Heart Failure: A Longitudinal Analysis of 86000 Individuals. JAMA Cardiol 2019;4:1102-1111.
2 McMurray JJV, Solomon SD, Inzucchi SE et al. Dapagliflozin in Patients with Heart Failure and Reduced Ejection Fraction. N Engl J Med 2019;381:1995-2008.
3 Packer M, Anker SD, Butler J et al. Cardiovascular and Renal Outcomes with Empagliflozin in Heart Failure. N Engl J Med 2020;383:1413-1424.
4 Armstrong PW, Pieske B, Anstrom KJ et al. Vericiguat in Patients with Heart Failure and Reduced Ejection Fraction. N Engl J Med 2020;382:1883-1893.
This article is from Murmurs Issue 41 (September – December 2021). Click
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