Heart & Stroke Conditions Explained



Cardiomyopathy is a medical term used to explain that there is a heart (Cardio) muscle (myo) disorder or problem (pathy).

Because it affects the heart muscle, it can affect the size and shape of your heart, and the thickness of the muscle wall. This then makes it more difficult for your heart to pump blood to all parts of the body.

Cardiomyopathy affects people of all ages, in many cases it is an inherited condition, caused by a genetic abnormality, and several family members can be affected.


There are four main types of Cardiomyopathy:

  • Dilated Cardiomyopathy(DCM)
  • Hypertrophic Cardiomyopathy(HCM)
  • Restrictive Cardiomyopathy(RCM)
  • Arrhythmogenic Right Ventricular Cardiomyopathy(ARVC)


Other types of cardiomyopathy include ischaemic cardiomyopathy due to a heart attack.

A severe viral infection, long standing high blood pressure, heart valve disease and certain drugs, such as too much alcohol, can also cause a cardiomyopathy.


Related topics: How your heart works, heart failure, hypertension (high blood pressure), heart attack, implantable cardioverter defibrillator (ICD)ECG, stress, coronary angiogrampacemaker CRT, ablation.



In the early stages, you may not have any signs and symptoms.

But as the condition advances, signs and symptoms usually appear. They vary from person to person and the type of cardiomyopathy.


Signs and symptoms may include:

  • Breathlessness with exertion or even at rest (due to fluid on the lungs)
  • Swelling of the legs, ankles and feet (due to fluid retention)
  • Bloating of the stomach (due to fluid retention)
  • Cough while lying down
  • Fatigue (due to low oxygen levels)
  • Irregular heartbeats that feel rapid, pounding or fluttering
  • Chest pain
  • Dizziness, lightheadedness and fainting


Some people have no symptoms at all. No matter what type of cardiomyopathy you have, signs and symptoms tend to get worse unless treated.



There are many possible causes of cardiomyopathy related to the type of cardiomyopathy you are diagnosed with.

There are four main types of Cardiomyopathy which are explained in relation to the underlying cause:


1. Dilated Cardiomyopathy (DCM)

Dilated Cardiomyopathy is a condition where the heart has become enlarged and the heart muscle does not pump as well as normal.

Dilated cardiomyopathy is usually caused by narrowed arteries and heart attacks but may also be due to untreated longstanding high blood pressure where the heart, having first thickened in response to the extra work, eventually starts to weaken and dilate.

Myocarditis or inflammation of the heart muscle from toxins like alcohol or certain cancer drugs can cause a dilated cardiomyopathy.

However, sometimes people present with a dilated cardiomyopathy and the cause is unclear. It is thought that their heart may have been damaged by certain viruses and that they may have a genetic weakness that makes their heart muscle more prone to injury.

There are also some families where a number of members are affected with a dilated cardiomyopathy and this is considered a hereditary cardiomyopathy.

Rarely, cardiomyopathy may occur in association with pregnancy and childbirth and is referred to as post partum cardiomyopathy which can be life threatening for both mother and child. Fortunately this is a rare condition.


2. Hypertrophic Cardiomyopathy (HCM)

Hypertrophic Cardiomyopathy is a condition where there is an increased thickening of the heart muscle around the ventricle (lower chamber) of the heart.

This is different to when the heart muscle may thicken in individuals as a result of high blood pressure or athletic training. In hypertrophic cardiomyopathy, however, the muscle thickening occurs without an obvious cause.

The main problem with this condition is that the muscle thickening makes the ventricle smaller which may prevent the heart from pumping the blood as efficiently as normal.

The thickening may be predominantly in the septum (central muscle wall) just below the aortic valve where the blood leaves the ventricle. It is this obstruction to the outflow of blood that may cause dizziness or collapse which can often be how these patients present.

Excessive exertion is not recommended for those with this condition. There is a significant family link with this condition and patients are advised to have their 1st degree relatives screened.


3. Restrictive Cardiomyopathy (RCM)

This is a rare form of Cardiomyopathy where the heart muscle becomes stiff and cannot relax which makes it difficult for the top chambers of the heart to fill. As a result the heart cannot pump blood around the body efficiently.


4. Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

In this condition there is a change in the structure of the right side of the heart muscle so that it is thinner and contains more fat and fibrous tissue than normal.

As a result of this the right heart may be more prone to abnormal rhythms and also not to pump as well as normal.

This is not a very common condition but there is a strong hereditary link and so your first degree relatives should be screened; your first degree relatives are your parents, children, brothers and sisters.


Takotsubo Cardiomyopathy in times of extreme stress

Takotsubo or ‘broken heart’ syndrome usually happens during a time of extreme stress (which gives it the name ‘broken heart’).

Episodes of extreme stress include bereavement or major accident. The left ventricle becomes enlarged and weakened.

It is often only temporary, and usually gets better with time.



In many cases, you can't prevent cardiomyopathy but being aware of the factors which may increase your risk can help to prevent it.

Also if diagnosed with cardiomyopathy prevention of complications is very important.


Risk factors include:

  • Family history
  • High blood pressure
  • Heart attack, coronary artery disease or viral infections that affected the heart
  • Alcoholism
  • Illicit drug use
  • Certain chemotherapy drugs and radiation used for cancer treatment
  • Metabolic diseases like diabetes or thyroid disorders
  • Diseases that can damage the heart such as amyloidosis (a build-up of abnormal protein), sarcoidosis (inflammation), or haemochromotosis (a build-up of excessive iron)
  • Connective tissue disorders.



Cardiomyopathy can be diagnosed in a variety of ways.

It may be that you have presented with symptoms or it may be as a result of a routine check-up.

Often, cardiomyopathy is a genetic condition. Because of this, if you have been diagnosed with cardiomyopathy it is important that you talk to your cardiologist or GP about assessing other family members for the condition.

It is important that all first degree relatives of a person with cardiomyopathy are medically assessed for the condition, even if they don’t have symptoms. If you have cardiomyopathy, your first degree relatives are your parents, children, brothers and sisters.

Your doctor will carry out a physical examination, take a personal and family medical history, and ask you about your symptoms. You may then have some heart tests including an electro-cardiogram (ECG), an echocardiogram (Echo) and exercise stress tests.

These tests look at the electrical activity and structure of the heart at rest and during exercise, and are non-invasive.

Most cases of cardiomyopathy can be identified with these tests. Occasionally there may be a need for further investigations, such as an electrophysiological (EP) study, magnetic resonance imaging (MRI), CT scan or angiogram.



Although cardiomyopathy cannot be cured, the treatment aims to reduce symptoms and prevent complications.

If the cause of your cardiomyopathy is found, treatment will also be directed at the underlying disease. It must be remembered that having a cardiomyopathy does not necessarily mean that you are going to have lifelong problems.

There are many individuals in whom this diagnosis was made who go on to have a long and healthy life.

Some people may be prescribed medications to improve the pumping ability of your heart, control your heart rate, lower blood pressure, reduce the build-up of fluid, reduce the risk of blood clots (anticoagulants) and reduce your risk of complications.

In some individuals, there is a risk of heart rhythm disturbance and so an implantable cardioverter defibrillator (ICD) is required. This device monitors your heart rhythm and delivers electric shocks when needed to control abnormal heart rhythms.

Sometimes, your doctor may recommend a pacemaker that coordinates the beats between the right and left side of your heart (biventricular pacemaker and CRT).

Rarely, people have surgery to remove some heart muscle or go on to have a heart transplant.

Support for You


The Irish Heart Foundation offers a range of free support services to those affected by heart disease or stroke that can greatly improve their quality of life. These include support groups, physical exercise classes, therapy sessions and more.

For more information on these supports, see our Patient Supports page.

If you have any questions about heart disease or stroke, you can also call the Irish Heart Foundation’s Nurse Support on (01) 668 5001 to speak to a nurse specialist who will answer your questions, and give you guidance and reassurance.

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