When muscle weakness affects breathing

Some muscle wasting conditions can affect the heart. This is because the heart is a special type of muscle. It works all the time to pump blood around your body. However, not all muscle conditions affect the heart.

Your neuromuscular team will tell you if you need heart tests and when to start them. A heart specialist (cardiologist) may talk to you about the results.

Regular heart tests can find changes in how your heart is working. This helps your doctor decide when to give you medicine and start treatment if you need it.

Heart problems do not often cause symptoms at first. But they can get worse over time and cause serious complications if they are not found and treated.

In some conditions, like Duchenne muscular dystrophy, doctors start treatment early in everyone to help protect the heart.

You cannot always tell if your heart has a problem. Heart problems can start slowly and may not cause any symptoms at first. But there are some things to look out for:

• Feeling very tired (fatigue)
• Losing weight
• Stomach pain
• Trouble breathing
• Swollen ankles and legs
• Chest pain or discomfort
• Heart racing or pounding (palpitations)
• Feeling dizzy or fainting

If you notice any of these, tell your GP or neuromuscular team. Other things can cause these symptoms – but it’s important to get them checked anyway.

If you have a condition known to affect the heart, your doctor will arrange regular heart tests even if you do not have symptoms.

If your muscle wasting condition affects the heart, it can lead to changes in the heart muscle or the way your heart beats.

Doctors usually check for two common types of heart problems: cardiomyopathy and arrhythmias.

Cardiomyopathy (heart muscle disease)

Cardiomyopathy means the heart muscle becomes stretched, thickened, or stiff. This makes it harder for the heart to pump blood around your body.

There are different types:

• Dilated cardiomyopathy – the most common type in muscle wasting conditions; the heart stretches and weakens, making it harder to pump blood.
• Hypertrophic cardiomyopathy – less common; the heart muscle becomes thicker, and the heart cannot fill and pump properly.
• Restrictive cardiomyopathy – rare; the heart muscle becomes stiff and does not relax properly between beats. This makes it harder for the heart to fill with blood in preparation for the next beat.

Doctors can often spot early signs of cardiomyopathy during regular heart tests.

Arrhythmia (heart rhythm problems)

An arrhythmia is when your heart does not beat in a regular way. It might beat at a rate that is too fast, too slow, or unsteadily.

• Atrial fibrillation (AF) – an irregular and often fast heartbeat from the upper part of the heart. It’s caused by a problem with the heart’s electrical signals.
• Supraventricular tachycardias (SVTs) – fast heartbeats that start in the upper part of the heart. They can make your heart race, and you could feel dizzy or unwell, but they’re usually not dangerous.
• Ventricular arrhythmias – abnormal heart rhythms that start in the lower part of the heart – usually fast and can be regular or irregular. These can be serious and may cause chest pain, fainting, blackout, or sometimes be life-threatening.
• Heart block – when electrical signals in your heart are delayed or blocked. This can make the heartbeat slow or unsteady.

You might notice signs like palpitations (like your heart racing or fluttering), feeling dizzy, fainting, or feeling very tired. But sometimes there are no signs, and arrhythmias are only found during a heart test.

If doctors do not find and treat arrhythmias, they can cause other heart issues. That’s why it’s important to monitor and catch them early.

These tests help your doctor check how well your heart is working. They can find any problems that might be developing, even if you feel fine.

Trained technicians or nurses carry out the tests. A heart specialist (cardiologist) will look at the results.

The type of tests you need and how often will depend on your condition or the signs your doctor finds.

• Electrocardiogram (ECG) – checks your heart’s electrical signals using sticky patches on your chest that record your heartbeat.
• ECG Holter monitor – records your heartbeat for a longer period (usually 24 to 48 hours). You wear sticky patches on your chest, connected to a small device you clip to your clothes while going about your day. Some newer monitors are just one small patch placed on your chest with no wires.
• Echocardiogram (echo) – a scan that uses sound waves (ultrasound). A doctor or technician moves a small device with gel over your chest to see how your heart is beating and pumping blood.
• Cardiac MRI – a scan that gives clear pictures of your heart and shows how blood moves through it. You lie still in an enclosed scanner for 30 to 90 minutes. The machine can be noisy, but it does not hurt.

If doctors find a problem early, it can often be managed well with medication. In some cases, a small device like a pacemaker may be needed later on.

Some people who are carriers of muscle wasting conditions, like Becker or Duchenne muscular dystrophy, may also need regular heart tests. Your neuromuscular team will let you know if this applies to you.

Not every medication or device is needed or right for everyone. Your heart specialist (cardiologist) will help you decide on the best treatment for you. They will also review your treatment regularly and arrange tests to see how well your heart is working.

Medication

If your heart is not working as well as it should, your doctor will give you medication to help. This might include:

• Beta blockers – slow your heartbeat by blocking stress hormones like adrenaline, helping your heart work more efficiently.
• ACE inhibitors or angiotension-2 receptor blockers (ARBs) – lower blood pressure by helping your blood vessels relax, making it easier for your heart to pump.
• Aldosterone blockers – help your body get rid of extra fluid and protect your heart from damage.
• SGLT2 inhibitors – help your heart work better and reduce strain. They do this by helping your body get rid of sugar through urine. Doctors use them for people with and without diabetes.
• Anticoagulants – help prevent blood clots that might cause a stroke.

Devices

• Pacemaker – a small device placed under the skin of your chest. It sends signals to keep your heart beating regularly.
• ICD (Implantable cardioverter defibrillator) – a larger device that can detect dangerous heart rhythms and give a small electric shock to correct them.

Self-care

There are things you can do to help look after your heart. These are important for everyone:

• Check your blood pressure and pulse now and then
• Keep a healthy body weight – being overweight puts more strain on your heart and muscles
• Eat a healthy, balanced diet
• Do regular movement and gentle exercise to help maintain muscle strength
• Minimise stress
• Avoid smoking
• Keep alcohol consumption below the recommended limit

You may want to carry an alert card or a medical alert bracelet. You could also use a built-in health app on your smartphone. These can provide useful information about your condition to medical staff, especially in an emergency. You can order or download condition-specific alert cards for some conditions from our alert card page.