Cardiac sarcoidosis: symptoms, tests and treatment when sarcoidosis affects the heart

The NHS describes sarcoidosis as a rare condition that causes small patches of swollen tissue, called granulomas, to develop in the organs of the body. It most often affects the lungs, lymph nodes and skin, but it can affect any organ. When granulomas form in the heart muscle or its electrical wiring, this is called cardiac sarcoidosis.

NICE Clinical Knowledge Summaries describes sarcoidosis as a multisystem disease of unknown cause characterised by non-caseating granulomas, with the lungs affected in approximately 90% of people, followed by the skin, and the eyes, brain, nervous system, liver and heart among the other organs. A cardiologist speaking at a SarcoidosisUK patient day said that cardiac involvement is where patients can occasionally develop potentially life-threatening presentations, and that it tends to present in people in their 40s and early 50s.

Cardiac sarcoidosis is not an inherited or infectious condition. The NHS says sarcoidosis is not infectious and that there is no evidence that it is inherited, although it can occasionally occur in more than one family member.

The NHS lists an abnormal heart rhythm (arrhythmia) among the symptoms that may occur if other organs are affected by sarcoidosis. The UK cardiologist at the patient day described the symptoms as sometimes non-specific, with palpitations and dizziness that can have many causes, and other symptoms arising when the heart muscle is not pumping as well as it should.

He described several ways cardiac sarcoidosis can present: heart block, in which the heart rate becomes very slow and a person can faint; ventricular tachycardia, a fast rhythm from the lower chambers of the heart; and heart failure, often due to scarring, which can mean the diagnosis was not picked up early enough. He also said that active inflammation in the heart can sometimes cause no symptoms and that people are increasingly being found through screening, for example when a person with known lung sarcoidosis has an ECG or scan that suggests heart involvement.

• Palpitations or a racing or irregular heartbeat.

• Dizziness, light-headedness or fainting.

• Breathlessness or ankle swelling if the heart pump is weakened.

• A very slow pulse in heart block.

• No symptoms at all in some people.

Fainting, a very fast heartbeat with chest pain, breathlessness or collapse should be treated as an emergency. Call 999 if you have sudden chest pain that does not stop, or palpitations with chest pain, breathlessness or feeling faint. If you have sarcoidosis and notice new palpitations, dizziness or fainting, contact your GP or specialist team promptly, since heart involvement can be missed when it is silent.

NICE Clinical Knowledge Summaries says lung function tests, blood tests and a 12-lead ECG may help confirm sarcoidosis, that people with suspected sarcoidosis should be offered a chest X-ray, and that people with findings consistent with sarcoidosis should be referred to an appropriate specialist depending on the organ system involved.

For the heart, the specialist at the patient day described cardiac MRI, which shows scarring and inflammation, and PET scanning, which is a special type of scan that looks for inflammation in the heart and other organs and can help measure how much there is. He said the pattern of scarring, together with the clinical history and presentation, is key to diagnosis, that PET is more sensitive for inflammation than MRI, and that people with pacemakers and defibrillators can usually have MRI if the device is MRI-conditional and reprogrammed.

He said heart biopsies are not routinely performed because of the small risk and because the disease is patchy, so a biopsy of an unaffected area could be falsely negative. Blood tests, ECG and chest X-ray support the diagnosis. Because cardiac sarcoidosis is rare, discussion by a specialist multidisciplinary team is usual.

NICE Clinical Knowledge Summaries says first-line treatment for sarcoidosis is usually corticosteroids, with immunosuppressants second-line and biologics as third-line treatment. The NHS says steroid tablets help relieve symptoms and prevent damage to organs by reducing inflammation and preventing scarring, but can cause side effects such as weight gain, mood swings and weakened bones if taken for a long time, so they are only used when necessary. An immunosuppressant may be recommended if steroids are not enough or there are concerns about side effects.

The cardiologist described that, in a person who presented with a dangerous rhythm, the priority is to protect against cardiac arrest, which means an implantable cardiac defibrillator may be advised, together with high-dose steroid treatment at first, followed by maintenance treatment to prevent inflammation returning. Heart failure medicines and pacemakers are used where heart function or conduction is affected. The exact combination is individual and decided by the specialist team.

Outlook varies widely. NICE Clinical Knowledge Summaries says approximately two-thirds of people with sarcoidosis experience remission within 2 to 5 years, but that in 10 to 30% it becomes chronic and requires prolonged treatment. Cardiac involvement tends to need longer-term specialist follow-up, and the earlier it is found, the more options there are. The specialist at the patient day noted that bringing inflammation under control is often associated with a better outcome.

The NHS suggests that people with sarcoidosis stop smoking, eat a balanced diet, maintain a healthy weight, reduce stress, exercise regularly and get enough sleep. It points to the Sarcoidosis UK website for support groups. People on long-term steroids or immunosuppressants should ask the team about bone protection and infection risk.

Cardiac sarcoidosis is usually managed on the NHS by a cardiologist with an interest in inflammatory heart disease, working with a respiratory or sarcoidosis team, and a small number of specialist centres receive referrals from across the country. A private cardiology consultation may allow faster access to an ECG, echocardiogram or MRI, but PET and combined multidisciplinary review are often available only at specialist centres, so it is worth asking how any private opinion will link with that specialist care.