Cardiac Sarcoidosis

Sarcoidosis is a rare inflammatory disease in which clusters of white blood cells, called granulomas, form and potentially damage various organs, affecting how well they work.

Cardiac sarcoidosis is name given to this disease when granulomas affect the heart, and is reported in anywhere from 5 percent of systemic sarcoidosis patients to 50 percent of them. It most often  affects people between ages 25 and 45. It is serious, and treatment is essential.

What is cardiac sarcoidosis?

Although tissue anywhere in the heart can be affected, sarcoid granulomas typically form in the heart muscle to interfere with the heart’s ability to pump blood. Specifically, these granuloma clusters affect the heart’s electrical system, causing arrhythmias or irregular heartbeats.

In severe cases, cardiac sarcoidosis can result in heart failure and be life-threatening.

Symptoms of cardiac sarcoidosis

Cardiac sarcoidosis may cause a complete heart block, arrhythmias, and congestive heart failure.

A complete heart block happens when electrical signals from the hearts upper chambers (atria) fail to reach its lower chambers (ventricles). This failure in cardiac sarcoidosis can considerable slow the heart rate, resulting in light-headedness, loss of consciousness, and potentially be fatal.

Sarcoid granulomas can interfere with the heart’s contraction rate and cause arrhythmias. Arrhythmias also cause light-headedness, fainting, and pose a risk of death.

Congestive heart failure describes the inability of the heart to pump enough blood to maintain essential body functions. The most common symptoms of congestive heart failure include a cough, shortness of breath, fatigue, and leg swelling.

Diagnosis of cardiac sarcoidosis

Cardiac sarcoidosis is very difficult to diagnose because most manifestations are not specific to the condition, leading doctors to initially look for  different causes.

Diagnostic tests for cardiac sarcoidosis include functional heart tests, imaging techniques to detect granuloma clusters, and tissue biopsies.

Functional heart tests:

Imaging techniques:

  • Positron emission tomography (PET) uses small amounts of a radioactively labeled molecule similar to glucose called 18F‐fluorodeoxyglucose (FDG). In the sarcoidosis-affected heart, FDG is primarily taken up by rapidly dividing immune cells, which can be detected by a PET scanner.
  • Cardiac magnetic resonance imaging (MRI) can be used to detect edema that is associated with inflammation and granuloma lesions as these result in an increased signal from the heart muscle.

Tissue biopsy:

  • A small heart tissue sample is taken through a vein, and viewed under a microscope for the presence of granulomas. But biopsies can lead to false negatives, because the disease process can be limited to certain areas of the heart.

Treatment of cardiac sarcoidosis

Sarcoidosis, including cardiac sarcoidosis, treatments focus on managing symptoms. Most medications act as immunosuppressors, agents that block the action of the immune system, to reduce inflammation. Corticosteroids such as prednisone, and cytotoxic medications such as methotrexate are most commonly used.

Heart medications, like those easing or lessening arrhythmia, may also be given. Another approach to treating arrhythmia is the use of a catheter ablation, which blocks abnormal electric signals in the heart.

An implantable cardioverter defibrillator (ICD) is a device that delivers electrical shocks to restore the heart’s normal heart rhythm and may be necessary in more severe cases where arrhythmia results in a stop of the heartbeat.


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