What is Cardiac Sarcoidosis and How Is It Treated?

Sarcoidosis is a chronic condition involving the immune system in which tiny clusters of inflammatory cells called granulomas develop in many parts of the body. Sarcoidosis mainly occurs in the lungs and lymph nodes but can also develop in the eyes, skin, nervous system, and heart.

Systemic sarcoidosis is diagnosed in approximately 200,000 Americans a year. Among people with systemic sarcoidosis, around 2-5% have cardiac sarcoidosis or involvement of the heart. Some estimates put the incidence of cardiac involvement at 20-30% in the US.

In this article, we will talk about cardiac sarcoidosis, including how doctors diagnose cardiac sarcoidosis, treatment options, and the complications of untreated cardiac sarcoid.

What is cardiac sarcoidosis?

As mentioned, systemic sarcoidosis is a chronic inflammatory condition that can affect multiple organs in the body—cardiac sarcoidosis occurs when the granulomatous inflammation directly affects the heart tissue.

The formation of sarcoid granulomas in the heart can interfere with the functioning of the heart and lead to cardiac symptoms like irregular heartbeats, palpitations, skipped beats, lightheadedness, fainting, shortness of breath, chest pain, and chest tightness.

Some of these symptoms are similar to those seen in pulmonary sarcoidosis (when it affects the lungs) and extracardiac sarcoidosis, making it difficult to identify patients with cardiac sarcoidosis.

Also, some patients can have silent cardiac sarcoidosis in which there are granulomatous lesions in the heart but no clinical manifestations, making it even more challenging to identify.

How is cardiac sarcoidosis diagnosed?

Doctors can use various tests to detect cardiac involvement in patients with systemic sarcoidosis.

Testing for suspected cardiac sarcoidosis may involve performing an electrocardiogram (ECG). Your doctor may ask you to wear a Holter monitor, which is a type of ambulatory ECG done using a portable device that monitors the heart for 24-48 hours and can detect atrial arrhythmias, ventricular arrhythmias, supraventricular arrhythmias, ventricular tachycardia, ventricular fibrillation, and other types of irregular heartbeats. If the results of these tests are abnormal and your doctor suspects cardiac sarcoidosis, they may want to obtain images of your heart.

Echocardiography is usually the first screening cardiac imaging test used to assess the functioning of the heart and the pressure in the pulmonary artery. However, while echocardiography provides information about heart function, it does not help diagnose early or accurate cardiac sarcoidosis specifically.

High-resolution imaging modalities like cardiac magnetic resonance imaging (MRI) are used to detect sarcoid granulomas in the heart and diagnose cardiac sarcoidosis. Other tests like cardiac positron emission tomography (PET) can show areas of active inflammation and fibrosis (scar tissue formation) and help diagnose sarcoidosis and manage the condition.

The gold standard for diagnosing sarcoidosis is an endomyocardial biopsy, in which doctors obtain a small sample of heart tissue and examine it in the laboratory for evidence of sarcoid granulomas. However, heart biopsies can be challenging and are not commonly done.

How is cardiac sarcoidosis treated?

The mainstay of treatment for cardiac sarcoidosis is immunosuppressive therapy with steroid treatment. This is used to decrease inflammation and disease activity and prevent cardiac sarcoidosis from progressing.

Besides corticosteroid therapy, medications such as beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, diuretics, and anti-arrhythmic drugs may be prescribed to treat heart failure and arrhythmias that occur as a result of cardiac sarcoidosis.

In addition to anti-arrhythmic therapy, doctors can also use device implantation (implantable cardioverter-defibrillator (ICD) or pacemaker implantation) to treat irregular heartbeats in symptomatic patients with cardiac sarcoidosis.

Programmed ventricular stimulation may be used to identify patients with cardiac sarcoidosis who are at high risk for arrhythmic events in the future. An ICD may be recommended in such patients to reduce the risk of life-threatening arrhythmias and improve survival rates.

Other possible treatments include catheter ablation, in which doctors guide a small tube into the heart to destroy the myocardium involved in causing an abnormal heartbeat.

The last resort for CS patients may be cardiac transplantation, in which doctors remove the diseased heart and replace it with a healthy heart taken from an organ donor.

Wrapping Up

Cardiac sarcoidosis is a chronic inflammatory condition of the heart in which granulomatous lesions develop in the heart tissue, leading to complications such as atrial and ventricular arrhythmias, systolic and diastolic dysfunction, complete heart block, heart failure, and even sudden cardiac death.

Diagnosis of cardiac sarcoidosis involves ECG, echocardiogram, Holter monitor, and cardiac imaging.

While there is no cure for systemic sarcoidosis or cardiac sarcoidosis, doctors can use medications, device implantation, and heart transplantation to treat patients with this chronic condition, slow down the progression of the disease, and improve quality of life and survival rates.

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