What is Cardiac Sarcoidosis?

Have you ever heard of cardiac sarcoidosis? Chances are, unless you or someone you know has been impacted by this rare illness, the answer is no. Cardiac sarcoidosis is a condition that causes granulomas(areas of tissue swelling) on the heart due to inflammation. While it may not be as well known as other heart diseases, it is important to understand its symptoms and treatments, especially since it can often be mistaken for other conditions.

Overview

If the topic of cardiac sarcoidosis has piqued your interest, it's important to first grasp the fundamentals of sarcoidosisbefore delving into the complexities of  how this condition specifically impacts the heart, and how it can affect those who experience it.

Sarcoidosis is a rare autoimmune illness in which the tissue develops granulomas, which are red, inflamed nodules composed of immune cells clumping together. Most patients with this illness present symptoms between the ages of 25 and 60.  Any organ can be impacted by this condition, although the lungs, skin, eyes, and  joints are the most frequently affected. In rare cases, the heart might be one of the impacted organs, and when this happens, the condition iscalled cardiac sarcoidosis.^1,2,3

Usually, the granulomas are found in the interventricular septum, which is the wall of the cardiac tissue that divides our heart ventricles, the lower chambers of the heart. Nevertheless, granulomas can also formcin the right or the left ventricle.⁴

It is less common for sarcoidosis to solely damage the heart; almost everyone diagnosed with cardiac sarcoidosis also has other organs that are affected, most frequently, the lungs. However, only 25% of those with cardiac sarcoidosisexperience symptoms of this illness. Cardiac sarcoidosis is more common in Japan, with half of the affected patients also having heart disease.³

Causes of cardiac sarcoidosis

The exact cause of cardiac sarcoidosis is still unknown.³ However, it has been linked to develop in patients who have received a heart-lung transplant from a sarcoidosis-positive donor.⁶

Sarcoidosis may also have a genetic tendency, according to studies that have established a connection between the disease and a family history of it as well as an increase in occurrence among people with a genetic predisposition that also smoke.⁷

Signs and symptoms of cardiac sarcoidosis

The symptoms of cardiac sarcoidosis can include irregular heartbeats or palpitations, chest pain, fatigue, shortness of breath, coughingand fainting. In thelater stages of the disease, swelling of the legs and exertional dyspnea, which is the medical term for the feeling of being out of breath during physical activity, can also be observed.^,

Management and treatment for cardiac sarcoidosis

Although there is currently no cure for cardiac sarcoidosis, the symptoms can be controlled. In order to do so, doctors may give different types of drugs to treat specific symptoms, such as solatol for the treatment of irregular heartbeat, as well as corticosteroids to suppress the systemic inflammation brought on by sarcoidosis, namely prednisolone. In addition, medical professionals may suggest immunosuppressants to slow the progression of cardiac sarcoidosis.³

An implanted cardioverter defibrillator (ICD) may be necessary in patients with severe cardiac sarcoidosis who have developed severe arrhythmias (irregular heartbeat) or heart failure. Patients who are more likely to experience a serious arrhythmic episode can also benefit from using the ICD. Although it is extremely rare, severe cases of cardiac sarcoidosis mayrequire a heart transplant.

Diagnosis of cardiac sarcoidosis

It is particularly challenging to diagnose cardiac sarcoidosis in people who have not been given a sarcoidosis diagnosis. However, a diagnsosis of cardiac sarcoidosisshould be considered in young individualswho have heart failure,heart block and/or ventricular arrhythmias (a typwof arrhythmia) without a clear cause.

When doctors suspect cardiac sarcoidosis, they will have patients undergo certain tests, such as:

• Magnetic resonance imaging (MRI) that is normally performed with specific contrast and enables to visualisethe damaged and inflamed spots within the heart muscles,  being the diagnostic testthat gives the most accurate information for cardiac sarcoidosis diagnosis 
• Echocardiogram, which is used to evaluate the pumping ability, the muscles and the valves of the heart
• Blood tests, such as angiotensin converting enzyme (CEA), brain natriuretic peptide (BNP), NTpro-BNP and Troponin
• Electrocardiogram (ECG) and a Holter monitor to provide information about the heart rate and rhythm. The ECG is used for monitoring these measures for short-periods of time while the Holter can be used for longer evaluations, for example when data needs to be monitores over a period of 24 hours
• Cardiac flurodeoxyglucose – Positron emission tomography (FDG-PET), which can be very helpful to guide immunosuppressive treatment by identifying the active places of inflammation

Nuclear medical scans, clinical electrophysiology studies, or a heart biopsy are other tests that can be used to identify cardiac sarcoidosis.^3,4,8

Risk factors

According to the European Respiratory Society Task Force committee, some of the variables that increase the risk of death from cardiac sarcoidosis are:

• Being older than 50 years
• Accumulation of the specific contrast into the heart tissue presented in MRI
• Cardiac inflammation identified by FDG-PET
• Echocardiogram presenting an abnormal global longitudinal strain
• Thinning of the interventricular septum, the membrane that divides the two ventricles of the heart
• Elevated levels of BNP or troponin in the blood
• Ventricular tachycardia
• The volume of blood that is pumped to the body from the left ventricle is under 40%^4,9 

Complications

The prognosis for cardiac sarcoidosis is typically poor because it is linked to several problems. That being said, whenever it is mistreated, there is a significant chance of developing cardiomyopathies, which are heart muscle illnesses, or ventricular arrhythmias, which can lead to sudden heart failure.⁶

Another complication is pulmonary hypertension. Pulmonary hypertension means that there is high blood pressure in the vessels that supply the lungs and usually develops in patients with advanced cardiac or lung sarcoidosis. In this situation, it can lead to major damage to the right side of the heart.⁸

In either of these circumstances, heart failure can develop. This can be deadly in patients with cardiac sarcoidosis, making itthe most significant complication.

FAQs

How can I prevent cardiac sarcoidosis?

Currently, there is no known strategy or mechanism to avoid cardiac sarcoidosis as the exact reasons behind the onset of this medical condition are still unidentified.

Is cardiac sarcoidosis fatal?

Cardiac sarcoidosis, when left untreated, can be very dangerous and fatal due to sudden heart failure. Early detection and intervention can help prevent adverse consequences and improve long-term outcomes.

How common is cardiac sarcoidosis?

Sarcoidosis can affect any organ in the body.However, just 25% of people with sarcoidosis have cardiac involvement, making it one of the less commonly affected organs. Isolated cardiac sarcoidosis is even rarer than cardiac sarcoidosis that co-exists withsystemic sarcoidosis.

When should I see a doctor?

Get medical attention whenever you see any indications or symptoms of cardiac sarcoidosis, like: 

• Irregular heartbeats
• Chest pain
• Fatigue
• Shortness of breath
• Coughing
• Fainting 

Summary

Although the reasons for its onset are still unknown, cardiac sarcoidosis is a form of the inflammatory disease known as sarcoidosis that affects the heart. Despite the fact that it occurs more frequently in Japan, it is still considered to be a rare condition. In young people who have heart failure, heart block, and/or ventricular arrhythmias without a known cause, tests should be performed to rule out cardiac sarcoidosis because this condition, if left untreated, can be fatal.