Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a usually congenital heart disease, in which the heart muscle is thickened – in particular in the left ventricle (lower chamber) – so that part of the heart becomes abnormally enlarged. Doctors also use the term “hypertrophy” to describe this thickening.

The role of the left ventricle is to pump oxygen-rich blood from the lungs to the rest of the body via the aorta (the main artery) so that the organs receive a supply of oxygen.

In around 70% of people with HCM, blood flow from the heart to the aorta is blocked and restricted by the thickened muscle – the medical term for this is obstruction. This is known as hypertrophic obstructive cardiomyopathy (HOCM). If there is no obstruction, doctors use the term hypertrophic non-obstructive cardiomyopathy (HNCM).

Globally, hypertrophic cardiomyopathy occurs in around 2 in every 1,000 people.

Many people with hypertrophic cardiomyopathy (HCM) have few symptoms or none at all for a long time.

When symptoms do occur, the following are the most common:

• shortness of breath or difficulty breathing during physical exertion
• tiredness (fatigue)
• chest pain (angina pectoris)
• circulatory problems or fainting – especially during or after physical exertion

Sometimes, cardiac arrhythmias (irregular heartbeat) may occur, e.g., heart palpitations. Persistent cardiac arrhythmias can be life-threatening.

In general, the first symptoms of HCM can occur at any age. However, shortness of breath and other symptoms that indicate heart failure don’t usually appear until middle age. Symptoms tend to occur at a later age in women than in men. However, they are often more severe.

The severity of the symptoms doesn’t always depend on whether and to what extent blood flow from the heart to the aorta is restricted – even people with a very limited blood flow (obstructive cardiomyopathy) may have few symptoms or none at all for many years. On the other hand, people without any restriction of blood flow (non-obstructive cardiomyopathy) may still suffer life-threatening complications such as cardiac arrest.

Hypertrophic cardiomyopathy is usually caused by inherited changes (mutations) in various genes that play an important role in the muscles of the heart. Around 60% to 70% of people with HCM have family members with the same condition.

Hypertrophic cardiomyopathy sometimes also occurs as the result of another illness.

In rare cases, no cause can be determined for the thickening of the heart muscle. When this happens, doctors use the term idiopathic hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is usually congenital, meaning that people are born with it. If symptoms occur, they aren’t normally present at birth and may emerge during childhood, adolescence or when the person reaches adulthood. Often, people with HCM remain unaware of their condition for many years.

Many people with hypertrophic cardiomyopathy have a normal life expectancy and are barely impacted in any way by their condition. For some people, however, the symptoms and complications can increase considerably over the course of their lives.

Every year, around 1% to 2% of people with HCM die as a result of the illness or its effects. The most common causes of death are sudden cardiac arrest, heart failure and blockage of the blood vessels due to blood clots (thromboembolisms).

Several factors increase the risk of sudden cardiac death. These include:

• loss of consciousness for no apparent reason within the last 6 months
• sudden cardiac death of a family member who also had HCM
• a left ventricle with a wall thickness of 30 mm or more
• no change in blood pressure during physical exertion or sport
• very severe symptoms

Hypertrophic cardiomyopathy (HCM) usually runs in families. For this reason, first-degree relatives (parents, children and siblings) of people with HCM are usually offered screening for early detection of the condition.

An in-depth consultation with a doctor is followed by a general physical examination. An echocardiogram is used to determine whether the heart muscles are thickened and whether heart function is restricted. A genetic test is sometimes performed in order to detect possible mutations.

People who have already been given a diagnosis of HCM should have a check-up every one to three years to monitor their condition – even if they have no symptoms. This involves checking the condition, functioning and stamina of the heart. These examinations allow doctors to more accurately assess the risk of sudden cardiac death.

They also allow them to determine whether an implantable cardioverter-defibrillator (ICD) is required. An ICD is a device used to treat heart diseases in which the heart abruptly begins to beat too quickly. As soon as the heartbeat accelerates, the device gives the heart one or more electric shocks to end the irregular rhythm. The heartbeat then returns to normal.

If hypertrophic cardiomyopathy (HCM) is suspected, a heart specialist (cardiologist) can perform various tests:

• An ultrasound scan of the heart (echocardiogram or “echo”) is normally sufficient to determine whether the heart wall is thickened and whether blood flow out of the left ventricle is being obstructed.
• Magnetic resonance imaging of the heart (cardiac MRI) may be used if thickening of the heart muscle is not definitively detected with an echocardiogram.
• An electrocardiogram (ECG) helps to detect any potential heart arrhythmias.

For more information about the diagnosis of heart diseases with an electrocardiogram and echocardiogram, see gesundheitsinformation.de.

Genetic testing is used if the methods described above fail to yield a clear result. It may also be useful after a definitive HCM diagnosis has been made. If a genetic change (mutation) is detected, doctors can then test the person’s close relatives to see if they are also affected. However, the mutations responsible for HCM cannot always be identified.

Hypertrophic cardiomyopathy (HCM) cannot be cured. However, there are many ways to treat the symptoms and avoid risks.

As long as people with HCM are experiencing no symptoms, no treatment is required. However, doctors recommend doing light endurance sport on a regular basis. Strenuous competitive sports, on the other hand, should be avoided. Weight loss can be beneficial if the person is overweight.

If the condition progresses and begins to cause symptoms, medication or surgery will be considered.

Drug therapy

Beta-blockers are normally used to treat symptoms such as chest pain or shortness of breath. These drugs slow the heartbeat and prevent cardiac arrhythmias. Alternatively, calcium channel blockers may be considered. These produce the same effect as beta-blockers and also improve blood flow. If these drugs alone are not effective, other options (such as diuretics, for example) are available.

Surgical procedures

If blood flow from the heart is severely obstructed due to thickening of the heart wall and if treatment with medication fails to provide effective relief from symptoms, heart surgery may be necessary. Heart surgeons can use various procedures to improve blood flow.

For people who are at a high risk of life-threatening cardiac arrhythmias, they generally use an implantable cardioverter-defibrillator (ICD).

For more information about ICDs, including how they work and advice for people who have these implants, see gesundheitsinformation.de.

Some people with HCM need a cardiac pacemaker to support the heart if other treatments prove ineffective or are not possible. If the heart is no longer able to supply the entire body with blood, a heart transplant may be necessary.

Many people with hypertrophic cardiomyopathy (HCM) are able to lead normal lives. A healthy lifestyle with plenty of exercise, a balanced diet and limited alcohol consumption is also recommended for people with this condition and can have positive effects.

Most people with HCM can engage in lower-intensity physical activities like golf, skating or walking without any concerns. Depending on their overall health and fitness, they may sometimes be able to do sports with a slightly higher level of physical intensity, such as skiing or some ball sports. It’s best to discuss which types of sport and exercise are suitable with a cardiologist.

It is advisable to choose healthy foods and to be mindful of portion sizes when eating. Larger meals can trigger chest pain – especially in people with obstructive cardiomyopathy.