Cardiac sarcoidosis is a rare disease in which clusters of white blood cells, called granulomas, form in the tissue of the heart. Any part of the heart can be affected, though these cell clusters most often form in the heart muscle where they can interfere with the heart’s electrical system (conduction defects) and cause irregular heartbeats (arrhythmias). Cardiac sarcoidosis can also result in heart failure. The disease tends to affect younger people, generally between 25 and 45 years old.
Most people diagnosed with cardiac sarcoidosis also have granulomas in other organs of the body, most commonly in the lungs (pulmonary sarcoidosis). It is estimated about 25% of individuals with sarcoidosis have cardiac involvement. Many experts believe that all individuals with any sarcoidosis should be screened for cardiac sarcoidosis to avoid lethal arrhythmias.