Cardiomyopathy explained – Dr Oliver Guttmann answers your questions

What is cardiomyopathy?

Cardiomyopathy is a general term for diseases of the heart muscle. In simple terms, it means the heart muscle has become abnormal. It might have become thickened, stretched, stiff or scarred, which makes it harder for the heart to pump blood around the body effectively.

There are three main types of cardiomyopathy:

• Hypertrophic cardiomyopathy (HCM) – the heart muscle becomes abnormally thick. In some people, the thickened muscle can obstruct blood flow leaving the heart.
• Dilated cardiomyopathy (DCM) – the heart becomes enlarged and weakened, so it can’t pump as strongly.
• Arrhythmogenic cardiomyopathy (ACM) – heart cells are replaced with scar and fatty tissue, which causes dangerous heart rhythm disturbances.

What causes cardiomyopathy?

Cardiomyopathy has many potential causes. Many cases are due to inherited genes that affect the proteins that make up heart muscle cells. If one person in a family is diagnosed, their relatives may be advised to undergo screening for cardiomyopathy and sometimes genetic testing.

Other people develop cardiomyopathy due to:

• Myocarditis, which is inflammation of the heart muscle, often caused by viral infections
• Autoimmune conditions
• Certain medications or chemotherapy   
• Excess alcohol
• Recreational drugs

A well-known cause of cardiomyopathy is takotsubo cardiomyopathy, commonly known as “broken heart syndrome”. This is when intense emotional or physical stress, such as bereavement, shock or trauma, temporarily weakens the heart muscle and can mimic a heart attack. This usually improves with time and supportive treatments.

What are the symptoms of cardiomyopathy?

Symptoms can vary depending on the type of cardiomyopathy and its severity. Some people have no symptoms at all and are diagnosed after a relative is found to have the condition. 

Common symptoms include:

• Chest pain
• Shortness of breath, especially on exertion or when lying flat
• Palpitations
• Fainting (syncope)
• Feeling lightheaded or as though you’re about to faint (presyncope)
• Fatigue
• Swelling of the legs (in more advanced cases)

How is cardiomyopathy diagnosed?

Cardiologists use several different tests to confirm a diagnosis and determine the type of cardiomyopathy a patient has:

• ECG (electrocardiogram) – records the heart’s electrical activity to show abnormal rhythms or signs of the heart muscle thickening.
• Echocardiogram – an ultrasound scan of the heart. This is often the most important test, showing the size, thickness and pumping strength of the heart, and whether there’s an obstruction.
• Holter monitor – a portable ECG worn for 24-72 hours (or longer) to detect intermittent rhythm abnormalities.
• Cardiac MRI scan – a detailed heart scan that gives high-resolution images of the heart muscle and can detect scarring or inflammation.

In some cases, we might also recommend exercise testing, blood tests or genetic tests.

What treatments are available?

Treatments depend on the type of cardiomyopathy and whether symptoms of heart failure are present. The goals are to relieve symptoms, prevent complications and improve the long-term outlook. Established medications include:

• Beta blockers – these slow the heart rate, reduce strain on the heart and improve symptoms.
• ACE inhibitors (or ARBs) – relax blood vessels and reduce the heart’s workload.
• Diuretics – reduce fluid overload.

One important newer medication for heart failure is sacubitril/valsartan (sold under the brand name Entresto). This is a combination drug that:

• Helps blood vessels relax
• Reduces fluid retention
• Makes it easier for the heart to pump
• Improves survival in certain patients with heart failure

This represents a significant step forward compared to older treatments alone.

What about the latest treatment developments?

For patients with symptomatic obstructive hypertrophic cardiomyopathy, mavacamten is a groundbreaking treatment. In hypertrophic cardiomyopathy, the heart muscle contracts too forcefully and becomes excessively thick. In some patients, this thickened muscle blocks blood flow leaving the heart – this is known as obstruction. This contraction is caused by abnormal interactions within the heart muscle proteins. Mavacamten is a cardiac myosin inhibitor that targets this underlying cause by reducing the excessive interaction between the proteins responsible for contraction inside heart muscle cells.

In practical terms, mavacamten:

• Reduces excessive contraction of heart muscle cells
• Allows the heart muscle to relax more effectively
• Decreases the thickness-related obstruction
• Lowers the pressure gradient inside the heart
• Improves symptoms such as breathlessness, chest pain and exercise intolerance

Clinical trials have shown that many patients experience significant improvement in symptoms, exercise capacity and quality of life. In some cases, mavacamten can reduce the need for invasive procedures.

Mavacamten directly addresses the underlying mechanism of obstructive hypertrophic cardiomyopathy rather than just treating symptoms, which represents a major shift towards precision, disease-targeted therapy.

It’s important that the heart is carefully monitored with echocardiography while taking mavacamten to ensure its pumping function remains in a safe range. When prescribed and monitored appropriately by specialists, it offers an important new treatment option for suitable patients.

How do you approach treating your patients?

The approach I take to each patient is highly personalised. First, I carry out a detailed clinic review of the patient, looking at their detailed medical and family histories, and constructing a family tree. I then perform thorough investigations to diagnose the cardiomyopathy, including genetic testing where appropriate. If a genetic cause is suspected, we may offer the patient’s relatives an assessment.

Once a diagnosis is confirmed, along with a cause, each patient’s treatment is tailored to their specific symptoms, heart function and risk profile. Cardiomyopathy is a long-term condition, so I provide ongoing follow-up with regular reviews to monitor their progress. 

If needed, we can also offer advanced therapies, including:

• Pacemaker implantation
• Implantable cardioverter defibrillator (ICD) to prevent sudden cardiac death
• In some cases, specialised procedures or surgery

The aim is always to combine careful investigation, modern therapies and personalised care to optimise each patient’s longevity and quality of life.

If you’re concerned about potential cardiomyopathy or have a relative with the condition, our cardiomyopathy experts are here to help. We offer appointments in as little as 24 hours, in-depth assessments with results within 48 hours and treatment plans tailored to your needs. Click here to find out more.