What is Cardiac Sarcoidosis?
Sarcoidosis is a health condition that can affect multiple parts of the body. It’s caused by a mixture of environmental, genetic, and inflammatory factors and results in the creation of non-healing lumps known as granulomas in various organs such as the lungs, eyes, skin, lymph nodes, and the heart. When these granulomas affect the heart, it’s called Cardiac Sarcoidosis (CS). Around 25% of patients with sarcoidosis, based on findings from scans and autopsies, have CS. It’s a rare and often serious condition.
CS is hard to diagnose. This is because sarcoidosis is sometimes seen as a condition that gets diagnosed when no other possible causes can be found. There’s no single test that can definitively diagnose it. The way sarcoidosis and CS in particular present themselves can greatly vary from person to person. CS could lead to heart failure, ventricular arrhythmia, myocardial infarction, or atrioventricular (AV) block. The most common symptoms seen are heart failure or issues with the heart’s electrical system. Around 25% of patients with CS don’t show any other signs of sarcoidosis in their body, and it’s not clear whether their prognosis is different from those with systemic sarcoidosis that affects the heart.
The most important thing to consider when predicting the outcome for patients with CS is the left ventricle ejection fraction (LVEF). This is a measure of how well the heart is pumping blood. To diagnose CS, doctors sometimes use a test called an endomyocardial biopsy, but this has limitations since it’s invasive and has a low success rate due to the inconsistent spread of the disease in the heart muscle tissue. Therefore, doctors often use more advanced scanning techniques to more accurately diagnose the condition, especially in patients who don’t show signs of sarcoidosis in other parts of their body.
What Causes Cardiac Sarcoidosis?
Cardiac sarcoidosis could be triggered by a combination of environmental influences, genetic factors, and issues with the body’s immune system not working correctly. Some believe that this disease could be the body overreacting to germs and various substances found in tissues, leading to ongoing inflammation, more like a bunch of small round lumps of cells found in the body. This chain of events can happen without any infection present.
Around 5% to 16% of patients with sarcoidosis have family members who have also had the disease. This pattern, especially in identical twins, suggests that genes could play a part in getting the disease. Some specific genes have also been connected with sarcoidosis, one of them being class II MHC HLA-DR3.
Exposure to certain environmental factors and how the body’s immune system responds to these influences are believed to be critical steps leading to Cardiac Sarcoidosis. Being exposed to certain environments or job-related risks may increase chances of developing sarcoidosis. For example, farmers, firefighters, and people exposed to insecticides or bioaerosols from mold consistently are at a higher risk. Sarcoidosis is also found to be more common in people who have been exposed to infectious bacteria such as Chlamydophila pneumoniae, Propionibacterium, and mycobacteria. One study discovered that 60% of patients with sarcoidosis had mycobacteria in their samples, while none of the control group had.
Cardiac sarcoidosis is known to resurface in transplanted organs of patients who have had sarcoidosis and then subsequently had a heart-lung transplant. There is proof of sarcoidosis appearing in a heart transplant recipient from a donor who had sarcoidosis. This suggests that the disease could be triggered by issues with the immune system or due to an infection.
Risk Factors and Frequency for Cardiac Sarcoidosis
Cardiac sarcoidosis (CS) affects 10 to 40 people per 100,000 in the United States and Europe. It affects more Black patients compared to White patients. However, only 5% of patients with another condition, sarcoidosis, get diagnosed with CS. Despite this, studies show that 25% of people with non-cardiac sarcoidosis also have CS, detected in various ways, including post-mortem examinations and imaging techniques. It’s worth noting that even people who have no symptoms can have CS; studies have found evidence of the disease in up to 26% of asymptomatic people.
On average, CS tends to be diagnosed at the age of 53 in the United States. It’s also slightly more prevalent in women (58%). The highest rate of sarcoidosis, along with its associated death rate, is found among Black women—in one study, 2% of this population were impacted by the disease.
Interestingly, the signs and symptoms of sarcoidosis tend to vary among different ethnic groups. For instance, Lupus pernio is more common in Puerto Rican and Black patients, while red, painful skin lumps (erythema nodosum) are more often seen in people of European descent. In Japan, where the rates of sarcoidosis are low, CS is a common symptom when sarcoidosis is present. Various studies in Japan reveal a prevalence of CS approaching 50%. Japanese people with sarcoidosis also have a higher incidence of heart-related deaths compared to those in other countries.
Signs and Symptoms of Cardiac Sarcoidosis
Cardiac sarcoidosis (CS) often presents with symptoms like heart palpitations, presyncope (feeling faint), and syncope (fainting), due to various irregular heart rhythms. These might include AV blocks, atrial fibrillation, or rapid heartbeats, either originating from above the ventricles (supraventricular) or from within the ventricles (ventricular tachycardia).
Be aware that presyncope and syncope might signal life-threatening irregular heart rhythms such as a severe AV block or ventricular tachycardia. These issues could trigger a sudden cardiac arrest. One small study found that more than 40% of cardiac sarcoidosis patients had AV block as their initial symptom, with ventricular tachycardia being the second most common.
These irregular heart rhythms could also lead to more subtle, chronic symptoms like fatigue, shortness of breath during exercise, and chest discomfort. The main symptoms for patients with right ventricular dysfunction, resulting from left ventricular dysfunction or high blood pressure in the lungs from lung sarcoidosis, could be shortness of breath and swelling in the lower limbs.
Patients might also display symptoms of heart failure such as shortness of breath during exercise, difficulty breathing while lying flat (orthopnea), or sudden nighttime breathlessness (paroxysmal nocturnal dyspnea). These symptoms are due to dilated or restrictive cardiomyopathy (heart muscle disease). There can also be breathing difficulties due to concurrent lung sarcoidosis. Sarcoidosis can cause inflammation in the coronary arteries (coronary vasculitis) and patients might experience symptoms of heart muscle ischemia.
During a physical examination, faster or slower than normal heartbeat (tachycardia or bradycardia), irregular pulse, swelling in the legs (pedal edema), or noticeable veins in the neck (jugular venous distention) might be noticed. A very audible second heart sound could indicate high blood pressure in the lungs, while additional heart sounds can point to issues with the left ventricle. Systolic or diastolic murmurs at the heart apex are common if the mitral valve is involved.
Sarcoidosis usually affects multiple organ systems. 90% of patients’ lungs are involved and it’s common to have skin, eyes, and neurological complications. Symptoms such as red, painful lumps on the skin (erythema nodosum), a chronic skin condition affecting the face (lupus pernio), eye inflammation (uveitis), or seizures might indicate systemic sarcoidosis.
Testing for Cardiac Sarcoidosis
Cardiac sarcoidosis (CS) can be diagnosed in two ways: histologically, meaning looking at changes in tissue under a microscope, or clinically, which involves the consideration of symptoms and test results. A surefire way to confirm CS is by finding noncaseating granulomas, a type of inflammation, in heart tissue obtained through an endomyocardial biopsy. However, this biopsy method only has a 25% to 36% chance of detecting CS due to the disease’s scattered occurrence in the heart muscle. By using a method called electrophysiological mapping in conjunction with the biopsy, the odds of finding CS can be increased to roughly 50%.
An electrocardiogram (ECG) is a test that can be used to detect problems in heart rhythm. If patients are experiencing palpitations as their only symptom, a method called ambulatory rhythm monitoring is better at spotting brief occurrences of heart block and abnormally fast heart rhythms. However, less than 10% of people with CS but without symptoms will have unusual ECG results.
Echocardiography, or heart ultrasound, could show signs of CS like thinning of certain heart walls or decreased heart functionality. However, it’s not the best tool for catching the early stages of the disease, and it’s possible for a patient with CS to have a completely normal result.
Cardiac magnetic resonance imaging (CMR) can provide valuable information about physical heart abnormalities commonly seen in patients with CS. If the patient has no contraindications, it’s recommended to use a substance called gadolinium to enhance the imaging. The use of gadolinium can spot heart fibrosis or swelling. Image enhancement usually occurs in specific parts of the heart but not the innermost layer. Late gadolinium enhancement is associated with unfavorable prognosis. For detecting CS, CMR has a sensitivity of 75% to 100% and specificity of 76% to 100%.
A test known as Fluorodeoxyglucose F 18 positron emission tomography (FDG-PET) can help identify active inflammation. It requires the patient to fast and avoid certain activities before the test to suppress normal heart cell activity and highlight the inflamed cells. The test can help identify the best spots to take a biopsy. The way the FDG is taken up varies in CS and can be affected by other heart conditions. Its sensitivity for detecting CS is roughly around 89% and specificity around 78%.
Both FDG-PET and CMR are frequently used together; they offer valuable information about the presence of active inflammation, its location beyond the heart, and physical characteristics of the heart. These tests may be used alone or together to assess how well treatments are working.
A biopsy that shows the noncaseating granulomas is the only definitive way to diagnose CS, but it only has a 25% to 36% success rate due to the disease’s scattered nature. In patients who also have sarcoidosis in other part of the body, it’s better to biopsy those areas due to higher success and lower complication rates. If an endomyocardial biopsy is necessary, FDG-PET or CMR can help show the best place to take a sample. For cases where CS is the only type of sarcoidosis present or when a biopsy from a different site doesn’t confirm diagnosis, an endomyocardial biopsy may be needed to confirm CS.
Treatment Options for Cardiac Sarcoidosis
Cardiac sarcoidosis, or CS, is a condition that can lead to potential heart problems. Therefore, its treatment goals are to slow down the progression of the disease, reduce the risk of sudden death due to heart problems, treat heart failure, and manage irregular heartbeats, also known as arrhythmias.
One common treatment plan involves immunosuppressive therapy. This type of therapy is designed to decrease your body’s immune response, which can help lower inflammation and lessen the chances of heart complications. This treatment is primarily recommended for individuals who have CS and are experiencing heart-related issues which includes symptoms like heart failure or certain types of arrhythmias. Also, immunosuppressive therapy is used when there’s evidence of inflammation in the heart, which can be discovered through tests like histological exams or FDG-PET scans, which checks for diseases in the body by detecting rays given off by a substance injected into your bloodstream.
At the beginning of the treatment, corticosteroids are typically used to reduce inflammation and fibrosis (a process where body tissues are replaced with fibrous connective tissue) in the heart. Corticosteroids may help lessen symptoms of ventricular tachycardia (a rapid heartbeat), reverse AV block (an issue with the electrical signals in the heart), and improve left ventricular ejection fraction (LVEF), a measure of how well your left ventricle (the main pumping chamber of your heart) is working.
Other medications can also be used with corticosteroids to minimize the usage of steroids. These include methotrexate or mycophenolate mofetil and are given to patients who the steroids don’t seem to be working for. Other treatment options include azathioprine, cyclophosphamide, and leflunomide.
Another aspect of managing CS involves dealing with arrhythmias. For controlling abnormal heart rhythms, pacemaker implantation could be a helpful procedure for individuals with CS and reversible conduction block, a condition where the electrical signals in the heart are impeded. An Implantable Cardioverter-Defibrillator (ICD), a device that can deliver electricity to restore a normal heartbeat, may be useful for those who need permanent pacing.
For patients with atrial fibrillation, a common kind of abnormal heart rhythm, anticoagulation or blood-thinning medication is recommended. Depending on the circumstances, therapeutic electrophysiology study, which tests the electrical activity of your heart to find where an arrhythmia is coming from, may be performed.
There are also specific treatment guidelines suggested for CS patients who experience ventricular tachycardia (a fast heart rhythm) that can’t be treated with immunosuppression therapy. Antiarrhythmic medications and a procedure called catheter ablation, which destroys areas in the heart that may be causing the abnormal heartbeat, are recommended for this.
Regarding ICD therapy, which uses a device to control fast or irregular heart rhythms, it’s recommended for CS patients experiencing significant heart complications. However, it’s not recommended for patients with continuous abnormal heart rhythms or in severe cases of heart failure.
What else can Cardiac Sarcoidosis be?
Cardiac sarcoidosis is a tricky condition to diagnose because it shares similar symptoms with many other diseases. One of these is Myocarditis, a condition where the heart muscle gets inflamed. Both conditions can cause heart rhythm problems, heart failure, and abnormal results on certain tests like Contrast-Enhanced Cardiac MRI and FDG-PET, which are imaging studies used to examine the heart. Myocarditis can sometimes come after a viral infection while another type of Myocarditis, called giant cell Myocarditis, can progress quickly. Doctors often need to take a tissue sample from the heart, using a procedure called endomyocardial biopsy, to differentiate between Myocarditis and cardiac sarcoidosis.
Heart muscle diseases, particularly one called arrhythmogenic right ventricular cardiomyopathy (ARVC), can also show similar symptoms as cardiac sarcoidosis. Heart rhythm problems are common in both these conditions. Symptoms like abnormal heart rhythms and heart failure are more frequently seen in cardiac sarcoidosis. Certain features visible on imaging studies favor one disease over the other. For example, late gadolinium enhancement, which is a feature seen on a specific type of heart imaging study, is usually not seen in ARVC. Instead, fat deposits inside the heart muscle are more common. Also, if a patient has other health issues typically seen with sarcoidosis, it makes cardiac sarcoidosis more likely.
Many diseases can cause similar results on the Contrast-Enhanced Cardiac MRI. These include heart attacks, heart muscle diseases like cardiac amyloidosis and hypertrophic cardiomyopathy, as well as certain genetic conditions like Fabry disease and hereditary hemochromatosis. Different patterns of enhancement on the MRI can help differentiate between these conditions. For example, hereditary hemochromatosis can also cause heart rhythm problems and heart failure, but it usually accompanies skin darkening, diabetes, and certain other changes on the MRI.
The growths or lumps seen in the heart muscle in cardiac sarcoidosis, called myocardial granulomas, can also be found in other conditions like tuberculosis, fungal infections, vasculitis, and immunodeficiencies. But these conditions usually present with other different symptoms that can help distinguish them from cardiac sarcoidosis. Medical history, physical examination findings, and other diagnostic tests can help in this differentiation.
What to expect with Cardiac Sarcoidosis
People suffering from systemic sarcoidosis with cardiac sarcoidosis (CS) have a worse overall outcome than those who have sarcoidosis without heart involvement. Certain factors like the occurrence of sustained ventricular tachycardia, a larger than normal left ventricular end-diastolic diameter (essentially, the size of one’s heart’s main pumping chamber when it is filled with blood before contraction), and a higher New York Heart Association (NYHA) class (which refers to the severity of a person’s heart disease) predict a higher risk mortality for patients with CS.
Heart failure and a reduced Left Ventricular Ejection Fraction (LVEF: a measurement that shows how well your left ventricle is pumping out blood) carry an especially poor prognosis. The 10 year survival rate being between 19% to 53% in the absence of a heart transplant.
When compared to other forms of sarcoidosis, cardiac sarcoidosis generally carries a worse prognosis. However, it is unclear whether so-called “silent” CS (that is, CS without symptoms) has a better prognosis than CS with symptoms. Some people with silent CS might not know they have the condition until they experience a sudden cardiac arrest.
Certain medical tests can also signal an increased risk for these patients. For instance, any signs of late-gadolinium enhancement (a term referring to abnormalities seen in cardiac MRI scans) or irregularities on an FDG-PET scan (a medical imaging technique) increase the risk of ventricular tachycardia (a fast heart rhythm) and cardiovascular death.
Poor function of the right ventricle (the chamber responsible for pumping pure blood back to the lungs) and late gadolinium enhancements associated with the right ventricle also have implications for the prognosis of CS patients. For example, among 260 patients with CS who had biopsy-proven diagnosis, poor RV systolic function (how well the right ventricle pumps blood) was linked to an increased risk of death from any cause. On the other hand, right ventricular late gadolinium enhancement was linked to unexpected sudden cardiac deaths and abnormal heart rhythms.
Possible Complications When Diagnosed with Cardiac Sarcoidosis
If left unattended, Cardiac Sarcoidosis, or CS, often leads to an enlarged and weakened heart (known as dilated cardiomyopathy) and an increased likelihood of irregular heart rhythms in the ventricles. When lung sarcoidosis doesn’t get better or becomes worse, which can lead to stiffening of lung tissues, it can cause the right side of the heart to fail. The most worrying outcome of CS that can occur unexpectedly is death, making it important to assess the risk and consider an Implantable Cardioverter Defibrillator, a device that can help restore normal heart rhythm.
Several additional complications may appear in patients with CS:
- Failure of the left or right heart
- A condition affecting the heart muscle, with or without heart failure
- An irregular heart rhythm in the ventricles
- Slow heart rhythms, including various degrees of blockage in the heart’s electrical signals, up to a complete blockage
- Sudden cardiac death
- Fast and irregular rhythms in the heart’s upper chambers, including atrial fibrillation
- High blood pressure in the arteries to your lungs leading to right heart failure
- Inflammation in the blood vessels of the heart and reduced blood flow to the heart muscle
Preventing Cardiac Sarcoidosis
Cardiac sarcoidosis, a condition where inflammatory cells collect and create clumps in the heart, can significantly affect the overall health of people with systemic sarcoidosis, which is a disease that can affect any organ in your body. This condition can lead to an increased chance of heart rhythm problems (ventricular arrhythmias) and even sudden cardiac death. If you have cardiac sarcoidosis, it’s important to understand that the disease may get worse over time. This means you’ll need ongoing checks and scans to monitor the disease and decide on the best treatment at the right time.
Patients could experience symptoms indicating multiple organs are affected and may need to consult specialists who focus on the specific organ affected for appropriate treatment. It’s crucial for those with cardiac sarcoidosis to start immune-system-suppressing drugs as soon as possible to slow down the worsening of the heart condition.
