Learning About Cardiac Sarcoidosis

Sarcoidosis (say "sar-koy-DOH-sus") is a disease that causes the immune system to form tiny clumps of inflamed tissue (granulomas). These clumps can form in many parts of the body, including the lungs, eyes, skin, and heart.

Cardiac sarcoidosis (CS) is a condition in which the clumps of tissue affect the heart. When these tissue clumps form in the heart muscle, they can affect the heart’s electrical system. They can also affect the heart's ability to pump blood. This makes CS one of the most serious forms of sarcoidosis.

About 1 in 4 people with sarcoidosis have some cardiac involvement. But many have no symptoms. Some people have CS without any other organ being affected. This is called isolated cardiac sarcoidosis.

The cause is not fully known. Researchers believe that in people who are prone to the condition, the immune system overreacts to something in the environment. This could be bacteria, viruses, dust particles, or chemicals.

Genetics may be involved in CS. About 5% to 16% of people with sarcoidosis have a relative who has had it.

You cannot catch CS from another person.

Many people have no symptoms, especially early on. When symptoms do occur, they can vary. It depends on which part of the heart is affected.

Common symptoms include:

• Palpitations. This is a feeling that the heart is fluttering, racing, or skipping a beat.
• Feeling dizzy or lightheaded or fainting.
• Shortness of breath, especially with activity.
• Fatigue.
• Swelling in the legs or ankles.
• Chest discomfort.

Diagnosing CS can be a challenge. That's because the symptoms can look like symptoms for many other heart conditions. And no single test can confirm CS on its own. Your doctor will review your symptoms and medical history. They'll also do a physical exam.

Several tests may be used. They include:

• Electrocardiogram (ECG or EKG). This records the heart’s electrical activity. It looks for rhythm problems.
• Echocardiogram. This uses sound waves to create images of the heart. This helps check the heart's structure and function.
• Cardiac MRI. This provides detailed images of the heart. A special dye may be used to highlight areas of scarring or inflammation.
• FDG-PET scan. This is a type of imaging that uses a small amount of radioactive material to find active inflammation in the heart.
• Blood tests. These check for signs of inflammation and rule out other conditions.
• Endomyocardial biopsy. This is when a small sample of heart tissue is removed and checked under a microscope for tissue clumps. This is the most definitive test. But CS tissue clumps are often patchy and can be missed, so it does not always give a clear answer.

Cardiac MRI and FDG-PET scans are often used together. That helps give the most complete picture. If sarcoidosis is already known to affect another organ, a biopsy of that area may be done instead of a heart biopsy.

Treatment focuses on reducing inflammation, slowing the disease, preventing dangerous heart rhythms, and managing heart failure if it happens. Not everyone needs treatment right away. Your doctor will decide based on your symptoms, test results, and how much the heart is involved.

• Corticosteroids are the main treatment for CS. They help reduce tissue clumps and inflammation in the heart.
• Other medicines that suppress the immune system may also be used. They may be added if steroids alone are not working. Or they may be used to reduce the amount of steroids needed.
• FDG-PET scans are often repeated about 3 months after starting treatment. This is to see how well the medicine is working.

• A pacemaker may be placed if CS is causing a slow or irregular heartbeat.
• An implantable cardioverter-defibrillator (ICD) may be used for people at higher risk of life-threatening heart rhythms. An ICD can detect dangerous rhythms and deliver a shock to restore a normal heartbeat.
• Medicines may be used to help control abnormal rhythms.
• In some cases, a procedure called catheter ablation may be used. It can treat an abnormal heart rhythm that does not respond to medicine.

• Standard heart failure medicines may be used if the heart isn't pumping well enough.
• In severe cases, advanced heart failure therapies or heart transplant may be considered.