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Cardiac Sarcoidosis: A Patient's Guide to the Heart Disease That Hides as Heart Block, Bad Rhythms, or Heart Failure

Medically Reviewed & Edited

Board-Certified Invasive Cardiologist
Encinitas and La Jolla, CA

Developed with digital research and writing assistance, then medically reviewed and edited by Dr. Rasch to ensure clinical accuracy and adherence to current evidence-based guidelines.

Last reviewed and updated on June 27, 2026

I want to walk you through cardiac sarcoidosis the way I’d talk through it in clinic. It’s one of those diagnoses I really care about getting right, because patients who get caught early do much better than patients whose diagnosis gets missed for years. The hard part is that sarcoidosis is a chameleon, it can look like an electrical problem, a rhythm problem, or a pumping problem, and it can hit the heart without showing up anywhere else in the body. So let me explain what it actually is, how it shows up, how we test for it, and what the treatment plan looks like once we know what we’re dealing with.

What Is Sarcoidosis, and How Does It Get Into the Heart?

Sarcoidosis is a disease where your immune system gets confused and forms small clumps of immune cells, called granulomas, in different organs. When those clumps land in the heart, we call it cardiac sarcoidosis.

What Sarcoidosis Actually Is

Sarcoidosis is what we call a multi-system inflammatory disease. That means it’s not a problem with one organ, it’s a problem with the immune system itself. The immune cells that should be off fighting infection start clumping together in tissues instead. Those clumps, which we call granulomas, are tiny, just visible under a microscope, but they get in the way of how an organ normally works.

Nobody knows exactly what causes sarcoidosis. The current thinking is that some people are born with a genetic tendency toward this kind of confused immune response, and then something (maybe an infection, maybe an environmental exposure, maybe a combination) sets it off. Once it starts, it can stay quiet for years, flare up, settle down, and flare again. Some people have a single episode and recover. Others have it on and off for decades.

The lungs are by far the most common place sarcoidosis shows up. About 90 percent of people with sarcoidosis have lung involvement, usually with swollen lymph nodes in the chest and some scarring in the lung tissue itself. The eyes are next most common, followed by the skin, the lymph nodes elsewhere in the body, the liver, and the nervous system.

Why the Heart Can Be Involved

The heart gets involved when those granuloma clumps end up in the heart muscle. Once they’re there, they cause problems in proportion to where they land and how active they are.

About 5 to 10 percent of patients with sarcoidosis have noticeable heart symptoms during their lifetime. But when researchers have looked at hearts after death in people who had sarcoidosis, they’ve found heart involvement in 20 to 30 percent of cases. A lot of cardiac sarcoidosis is silent until it isn’t.

The trickiest part is that some people have heart involvement without any obvious sarcoidosis anywhere else. This is called isolated cardiac sarcoidosis, and it accounts for about a quarter of cases. These patients have no lung disease, no skin findings, no eye involvement, just heart symptoms. Their diagnosis is harder than average because there’s no obvious extra-cardiac clue to anchor the workup.

What Granulomas Do to the Heart

A granuloma is small, but it sits where it shouldn’t. Imagine a tiny patch of scar tissue forming in a piece of muscle that has to keep contracting and conducting electrical signals. The granuloma disrupts whatever it touches. If it lands on the heart’s electrical wiring, you get a conduction problem. If it lands in the heart muscle and sets up an unstable patch, you can get dangerous rhythms. If granulomas spread widely through the muscle, the heart can’t pump as well as it should.

Sarcoidosis granulomas have a favorite spot in the heart: the upper part of the wall between the two pumping chambers. We call this the basal interventricular septum. The heart’s electrical wiring (the AV node and the bundle of His) runs right through that area. When granulomas land there, they jam up the wiring. That’s why heart block is such a classic way for cardiac sarcoidosis to show up.

Who Tends to Get Cardiac Sarcoidosis

A few patterns help me know when to look for it:

How Cardiac Sarcoidosis Shows Up (Three Patterns)

When cardiac sarcoidosis becomes obvious, it tends to do so in one of three ways: a problem with the heart’s electrical wiring (heart block), a problem with the heart’s rhythm coming from the bottom of the heart (ventricular tachycardia), or a problem with the heart muscle’s strength (a weakened, dilated heart). Sometimes more than one of these happens at the same time.

Pattern 1: Heart Block

What Heart Block Means

Your heart has its own electrical system. A signal starts in the top of the right side (the SA node, your natural pacemaker), travels down to the AV node (a relay station between the upper and lower chambers), then through a structure called the bundle of His and out into the bundle branches that tell the bottom of the heart to squeeze. The whole sequence happens about once a second when you’re at rest.

Heart block is when that signal gets interrupted somewhere along the way. There are several levels. First-degree heart block just means the signal takes a little longer than it should to travel. Second-degree heart block means some of the signals don’t make it through at all. Third-degree heart block (also called complete heart block) means none of the signals from the top of the heart make it to the bottom, and the bottom of the heart has to take over with its own slower, less reliable backup pacing.

Why Sarcoidosis Causes Heart Block

Think back to that favorite spot for sarcoidosis granulomas, the basal interventricular septum. The AV node and the bundle of His run right through there. When granulomas pile up in that area, they physically interrupt the electrical signal. If the inflammation is caught early, sometimes the conduction can recover with treatment. If the granulomas have already turned into scar, the block is usually permanent and the patient needs a pacemaker.

The Classic Patient I See in Clinic

A 42-year-old who never had heart problems shows up in the emergency room because he felt lightheaded walking up the stairs at work. His EKG (electrocardiogram, the heart-tracing test) shows complete heart block. His coronary arteries look clean on a CT scan. His echocardiogram (the ultrasound of his heart) shows a slightly thinned upper part of the wall between the chambers and mildly reduced pumping. He’s never smoked. He has no family history of heart disease.

That patient gets a temporary external pacemaker, and the question that should follow immediately is: why does a 42-year-old without coronary disease have complete heart block? The answer, in many cases like this, is cardiac sarcoidosis, and recognizing the pattern before a permanent pacemaker goes in matters, because the diagnosis changes what kind of device he needs and starts the medical treatment that can prevent the disease from progressing.

Pattern 2: Dangerous Heart Rhythms (Ventricular Tachycardia)

What Ventricular Tachycardia Is

Ventricular tachycardia, or VT, is a fast heart rhythm that comes from the bottom chambers of the heart. Normally the bottom chambers should beat in coordinated response to signals from the top. In VT, the bottom chambers start firing on their own, often very fast (150 to 250 beats per minute), in a way that doesn’t pump blood effectively. Short runs of VT can feel like palpitations or a fluttering. Sustained VT can cause lightheadedness, fainting, chest pain, or sudden cardiac arrest.

Why Sarcoidosis Causes VT

The patches of inflammation and scar that sarcoidosis leaves in the heart muscle can become electrically unstable. The boundary between healthy muscle and scar is the perfect setup for a re-entrant rhythm, where an electrical signal gets stuck in a loop and the heart keeps firing on its own. Cardiac sarcoidosis is one of the textbook causes of VT in patients whose hearts otherwise look pretty normal on an initial ultrasound.

Why VT From Sarcoidosis Worries Me Most

Some patients with cardiac sarcoidosis show up after a sudden cardiac arrest, which is the worst-case version of this pattern. Cardiac sarcoidosis is found in 3 to 10 percent of younger patients with otherwise unexplained sudden cardiac death. If a patient survives an arrest and turns out to have cardiac sarcoidosis, we need to do two things at once: calm down the inflammation that caused the rhythm, and protect them from another arrest with an implantable defibrillator (a device that watches your heart and shocks it back to a normal rhythm if a dangerous one starts).

Pattern 3: A Weakened, Dilated Heart (Cardiomyopathy)

What This Looks Like Clinically

The third way cardiac sarcoidosis shows up is as a heart muscle problem. Granulomas spread through different parts of the heart wall and the muscle’s ability to pump weakens. On an echocardiogram, the heart looks larger than normal and the squeeze (called the ejection fraction, the percentage of blood pumped out with each beat) is reduced.

The patient might notice shortness of breath when walking up stairs, swelling in the feet and ankles, a need to sleep on more pillows than they used to, or a general decline in exercise tolerance. These are the same symptoms any cause of heart failure can produce, which is part of why cardiac sarcoidosis often gets mislabeled as “idiopathic non-ischemic cardiomyopathy” (heart failure with no known cause).

What the Heart Actually Looks Like

The clue that a weakened heart is from sarcoidosis rather than something else is often in the imaging. The wall thinning tends to be patchy and uneven, sometimes concentrated in the upper part of the wall between the chambers. On a cardiac MRI, the late gadolinium enhancement pattern (which I’ll explain below) often shows scar that doesn’t match the territory supplied by any single coronary artery. That mismatch is one of the most useful diagnostic clues.

Late-stage cardiac sarcoidosis can leave wall thinning so severe that small aneurysms (bulges in the wall) develop, especially along the bottom or side of the heart. Those areas can become electrically unstable too, which is part of why patients with cardiomyopathy from sarcoidosis often have arrhythmias on top of the pumping problem.

How We Diagnose Cardiac Sarcoidosis

There’s no single blood test that confirms cardiac sarcoidosis. The diagnosis comes from putting together several pieces: the clinical pattern, an echocardiogram, a cardiac MRI, a PET scan, and a search for sarcoidosis elsewhere in the body. The Heart Rhythm Society released a structured set of criteria in 2014 that walks us through how to make the diagnosis reliably.

The Workup Has Two Sides

The 2014 Heart Rhythm Society criteria give us two paths to the diagnosis. The first is finding granulomas directly on a biopsy of the heart muscle. That’s the most direct evidence, but it’s not used often because the granulomas tend to be patchy, and a small biopsy sample can miss them even when they’re present.

The second path is the clinical pathway: find granulomas elsewhere in the body (often the lungs, lymph nodes, or skin), combine that with the right cardiac findings (heart block, ventricular arrhythmia, scar pattern on MRI, active inflammation on PET, or unexplained reduced ejection fraction), and make the diagnosis without a heart biopsy. This is the path most patients are diagnosed through.

Step 1: The Story I Take in Clinic

The conversation usually starts with the symptom that brought you in (the syncope, the palpitations, the shortness of breath), but I’ll ask about more than that. Have you had any unexplained cough or shortness of breath that wasn’t ever fully explained? Any rashes, especially raised purple or red bumps on the shins (those are called erythema nodosum) or unusual rashes elsewhere on the body? Any eye redness or vision changes that were called uveitis? Any swollen lymph nodes in the neck or armpits that nobody figured out? Any family history of sarcoidosis?

I’ll also ask about your ancestry, because the disease is more common in Black/African American and Scandinavian patients. None of these questions are confirmatory on their own, but they shift my level of suspicion before I start ordering tests.

Step 2: The Echocardiogram

The echocardiogram is the ultrasound of your heart. You lie on your side, a technician puts gel on your chest and presses an ultrasound probe against you, and the machine builds up a moving picture of your heart in real time. It takes about 30 to 45 minutes and there’s no radiation.

What I’m looking for on the echocardiogram in a sarcoidosis workup: thinning of the upper part of the wall between the chambers, regional wall motion problems that don’t match the territory of any single coronary artery, reduced ejection fraction, and any aneurysm-like bulges. Strain imaging (a newer technique that measures how much each part of the heart muscle stretches with each beat) can sometimes pick up problems that the basic picture misses.

Step 3: The Cardiac MRI

What a Cardiac MRI Feels Like

A cardiac MRI is an imaging test that uses a strong magnet (not radiation) to take detailed pictures of the heart muscle itself. You lie on your back in a tube-shaped scanner for about 45 minutes to an hour. You’ll be asked to hold your breath several times for short stretches (10 to 20 seconds each) while the most important images are being taken. The scanner is loud (you’ll wear earplugs or headphones), but it doesn’t hurt. About halfway through, the technician will inject a contrast dye called gadolinium through a small IV in your arm. The dye doesn’t burn or feel cold the way some imaging contrast does, most patients don’t feel it going in.

What I’m Looking For on the MRI

The most useful part of the cardiac MRI for sarcoidosis is what we call late gadolinium enhancement. After the contrast goes in, the dye washes out of healthy heart muscle quickly but lingers in areas where the muscle is scarred or fibrotic. Pictures taken about 10 to 20 minutes after the contrast injection light up those scarred areas as bright spots against the dark background of normal muscle.

The pattern of those bright spots matters more than just whether they’re present. In sarcoidosis, the scar pattern is usually patchy and tends to involve the middle or outer parts of the heart muscle wall, especially in the upper part of the wall between the chambers. That pattern is different from the scar a heart attack leaves (which follows the territory of a blocked coronary artery and goes all the way through the wall, starting from the inside), and it’s different from the scar of cardiac amyloidosis (a different infiltrative disease that produces a more uniform, sub-surface pattern).

A cardiac MRI also gives me a precise measurement of pumping strength and chamber size, and it can spot signs of active swelling in the muscle (which suggests inflammation that’s still ongoing) as opposed to old, burnt-out scar. The 2013 Greulich study published in JACC: Cardiovascular Imaging showed that finding late gadolinium enhancement on the cardiac MRI predicts future bad events in suspected cardiac sarcoidosis patients.

Step 4: The PET Scan With the Special Diet

Why the Diet Matters So Much

The PET scan is the test that tells us whether the inflammation is still active right now, versus burnt-out scar from inflammation that’s already done its damage. That distinction matters a lot for treatment, because steroids work on active inflammation but not on old scar.

The trick with a PET scan of the heart is that PET imaging uses radioactive sugar (called FDG) as the tracer. Inflammatory cells take up sugar, so they light up on the scan. But healthy heart muscle also burns sugar for energy. If your heart muscle is happily eating sugar at the time of the scan, the whole heart lights up and we can’t see the patches of inflammation.

To get around this, we ask you to follow a special diet for 24 hours before the scan that shifts your heart’s metabolism from sugar to fat. When the heart is running on fat instead of sugar, normal heart muscle goes dark on the PET scan, and any patches of inflammation (which still use sugar) light up clearly.

What You Eat for 24 Hours Before the Scan

The diet is high-fat, low-carbohydrate, and no sugar. The day before the scan, you’ll eat foods like:

You’ll avoid:

After dinner the night before, you’ll be asked to fast (water and black coffee allowed) for the 12 to 18 hours leading up to the scan. The fast is part of the metabolic shift, the more strictly the diet is followed, the cleaner the scan turns out.

If the diet isn’t followed exactly, the scan can be uninterpretable. If you’ve ever had a PET scan come back as “non-diagnostic,” the diet is the most likely reason. I’m strict about this with my patients because a non-diagnostic PET is wasted time and money and we have to redo it.

What Scan Day Looks Like

You’ll arrive at the imaging center after your fast. They’ll check your blood sugar (it should be in a normal range if you’ve followed the diet correctly). The radioactive sugar is injected through an IV, and you’ll rest quietly for about 30 to 60 minutes while it distributes through your body. Then the actual PET scan takes about 30 minutes, lying on a table that moves through a donut-shaped scanner. It’s quieter than an MRI and there’s no contrast injection during the scan itself.

The radioactive sugar wears off the same day. You can go home, drive yourself, and eat whatever you want. You’ll be a little radioactive for about 24 hours, so I usually ask patients to avoid prolonged close contact with pregnant women or small children during that window, as a basic precaution.

Step 5: Looking for Sarcoidosis Elsewhere in Your Body

Even after the heart imaging, the workup includes a careful search for sarcoidosis in other organs, because finding granulomas anywhere in the body strengthens the diagnosis without needing a heart biopsy.

Typical extra-cardiac workup:

Step 6: Tissue Biopsy (Sometimes)

If the diagnosis is still uncertain after the imaging and extra-cardiac workup, we sometimes biopsy a piece of the heart muscle (called endomyocardial biopsy). It’s done through a vein, with a small catheter advanced into the right side of the heart, and tiny pieces of muscle are taken from the inside of the wall. The yield is modest (the granulomas are patchy and the biopsy is small), but if the biopsy is guided by where the PET or MRI shows the worst involvement, the yield improves.

If a swollen lymph node in the chest can be biopsied through an EBUS procedure (a special bronchoscope with an ultrasound probe), that’s often a cleaner way to get a granuloma confirmed than going for a heart biopsy directly.

How We Treat Cardiac Sarcoidosis

Treatment has three layers stacked together. The first layer is calming down the inflammation with steroids (sometimes plus a second drug). The second layer is protecting you from dangerous rhythms with a pacemaker, a defibrillator, or both. The third layer is supporting your heart’s pumping with the standard heart failure medications. Most patients need pieces of all three.

Layer 1: Calming Down the Inflammation

Prednisone, the First-Line Drug

Prednisone is the steroid we use most. The dose I start with is usually 30 to 40 milligrams a day. Higher doses (up to 60 milligrams) are sometimes used in severe presentations, but the side effects of high-dose steroids over long periods are real, so I aim to use the lowest dose that gets the job done.

Once the inflammation is calm (which we usually confirm by repeating the PET scan a few months in), the prednisone gets tapered down slowly over the next 6 to 12 months. A typical taper might look like: 40 milligrams for a month, 30 milligrams for a month, 20 milligrams for a month, then slower drops down to 10, 7.5, 5, and eventually off if the patient stays in remission.

What to Expect on Prednisone

Patients on prednisone notice a few things almost immediately. The most common is increased appetite, sometimes with weight gain. Some people get a “moon face” appearance from fluid retention in the cheeks. Others notice mood changes, sometimes feeling energized or jittery, sometimes feeling more anxious or down. Sleep can be disrupted, especially if the dose is taken late in the day, which is why I have patients take it in the morning.

I’ll check your blood sugar and your blood pressure more often on prednisone, because both can rise. Patients with prediabetes can tip into diabetes on high-dose steroids. Patients with already-high blood pressure may need their blood pressure medication adjusted upward.

Side Effects to Watch For Over the Longer Term

The longer you’re on prednisone, the more some other side effects become relevant:

Steroid-Sparing Medications

For patients who can’t tolerate prolonged steroids, who relapse during taper, or who have severe disease, we add a second medication to let us use less prednisone. The most common one is methotrexate. Others include azathioprine and mycophenolate. In the toughest, most refractory cases, biologics like infliximab (a TNF blocker) can be used, though the evidence base for these in cardiac sarcoidosis is smaller than for the inflammatory diseases they were originally developed for.

I usually coordinate the medication decisions with a rheumatologist or pulmonologist who manages sarcoidosis day in and day out. They have more experience with the steroid-sparing agents than most cardiologists do.

Layer 2: Protecting You From Dangerous Rhythms

When You Need a Pacemaker

A pacemaker is a small device implanted under the skin near your collarbone, with one or two wires that run into the heart through a vein. It watches for the heart’s natural electrical signal and provides a backup beat if the natural signal is too slow or doesn’t conduct properly.

In cardiac sarcoidosis, the pacemaker indications are similar to other causes of heart block: complete heart block, advanced second-degree block, or significant pauses that are causing symptoms. The wrinkle is that sarcoidosis tends to come with elevated arrhythmia risk beyond just the conduction problem, which leads to the next point.

When You Need a Defibrillator (ICD)

An implantable cardioverter-defibrillator (called an ICD) looks similar to a pacemaker but does more. It watches for dangerous fast rhythms from the bottom of the heart, and if one starts, it shocks the heart back to a normal rhythm. The shock is quick (it feels like a hard punch to the chest) and life-saving.

Patients with cardiac sarcoidosis are at higher risk of ventricular tachycardia than the conduction problem alone would suggest. That’s because the granulomas that disrupt the conduction system are usually accompanied by other granulomas in the heart muscle that can set up dangerous rhythms.

Why Most Sarcoidosis Patients Get a Combined Device

Because of that elevated arrhythmia risk, the 2014 Heart Rhythm Society guidelines recommend that when a cardiac sarcoidosis patient needs pacing for heart block, the device put in should be one that can also defibrillate. That means most of these patients get a defibrillator-capable device rather than a plain pacemaker. The exact device choice depends on other factors (ejection fraction, MRI findings, electrophysiology study results), but the default skews toward defibrillation capability.

A subset of patients also benefit from cardiac resynchronization (a three-wire device that helps the bottom chambers contract in sync) if their pumping is weak and the QRS on the EKG is wide.

Medications for Bad Rhythms

For patients who keep having ventricular tachycardia despite their device, we add antiarrhythmic medications. Amiodarone is the most commonly used because it works when others don’t, but it has a long list of side effects (thyroid, lung, liver, eye, skin) that have to be monitored carefully. Sotalol is another option in selected patients.

Catheter ablation, where an electrophysiologist threads catheters into the heart and burns the unstable patches that are causing the bad rhythm, is sometimes used when medications aren’t enough. The ablation is harder in sarcoidosis than in many other conditions because the disease is patchy and progressive, but in experienced hands it can reduce the burden of shocks.

Layer 3: Supporting the Heart’s Pumping

The Four Pillars of Heart Failure Therapy

If your pumping (ejection fraction) is reduced, you get the standard four medications we use in heart failure with reduced ejection fraction:

  1. Sacubitril-valsartan (brand name Entresto), or an ACE inhibitor or an ARB (angiotensin receptor blocker) if Entresto isn’t tolerated. These lower blood pressure and protect the heart from chronic strain.
  2. A beta-blocker (like carvedilol, metoprolol succinate, or bisoprolol). Beta-blockers slow the heart rate, reduce strain, and improve long-term survival.
  3. A mineralocorticoid receptor antagonist (spironolactone or eplerenone). These block a hormone called aldosterone that drives fluid retention and scarring.
  4. An SGLT2 inhibitor (dapagliflozin or empagliflozin). Originally developed for diabetes, these drugs reduce heart failure events and slow kidney disease, even in people without diabetes.

Why They All Matter

These four drug classes each work through a different pathway, and the survival benefits stack. A patient on all four lives longer, gets hospitalized less often, and feels better than a patient on one or two. The trick is starting them in a sensible order and titrating each up to the target dose as blood pressure and kidney function allow.

The standard heart failure drugs treat the symptoms and slow the progression, but they don’t fix the underlying inflammation. That’s why they’re layer three, not layer one. Without the steroids in layer one, the inflammation keeps causing more damage even while the heart failure drugs are working on the consequences.

What to Expect Long-Term

Most cardiac sarcoidosis patients can be stabilized for years with the right combination of immunosuppression, device therapy, and heart failure medications. Some patients have a single episode that responds to a year of treatment and never relapses. Others have a relapsing course that requires ongoing maintenance. A smaller group progresses despite optimal therapy and may eventually need a heart transplant.

Will I Need to Be on Steroids Forever?

Probably not. The typical first course of prednisone is 6 to 12 months at progressively lower doses, with the goal of getting you completely off if you stay in remission. Some patients are able to do that. Others need a low maintenance dose (often 5 to 10 milligrams of prednisone) plus a steroid-sparing medication to keep the inflammation suppressed long-term. The plan is individualized, and it can change over time.

Can the Damage Reverse?

Some of it can, yes. Inflammation that’s caught early and treated before it scars the muscle can resolve completely on the PET scan. Heart block that’s still in an inflammatory phase sometimes recovers with treatment, occasionally enough that a pacemaker that was originally needed becomes unnecessary. Pumping function can improve when the inflammation calms down.

What doesn’t reverse is established scar. Once the inflammation has been there long enough to leave fibrous scar tissue, that area stays scarred even after the inflammation is gone. That’s part of why we want to catch the diagnosis early, before the damage is locked in.

The Surveillance Plan

After your initial treatment, I’ll see you regularly to track how things are going. The typical schedule is:

Signs Things Are Going Well

The pattern that says we’re winning includes: PET scan that no longer shows active inflammation, stable or improving ejection fraction on echo, no new conduction problems, no ICD shocks, no hospital admissions for heart failure, and you feeling better than you did at diagnosis.

Signs Things Are Going Poorly

The pattern that says we need to escalate includes: PET that lights up again after being quiet (a relapse), drop in ejection fraction, new arrhythmias or ICD shocks, hospitalization for heart failure, new findings of sarcoidosis in other organs, or worsening side effects from the medications. When any of these happens, we revisit the plan, sometimes restart higher-dose prednisone, sometimes add a steroid-sparing agent, sometimes refer to advanced heart failure for transplant evaluation.

Pattern Recognition: When to Look for Cardiac Sarcoidosis

I want every cardiologist (and every patient) to know the patterns that should prompt a sarcoidosis workup:

Higher pretest probability in Black/African American and Scandinavian populations means I lower the threshold for the workup in those patients.

When to Call Me, and When to Call 911

Patients with cardiac sarcoidosis are at elevated risk for some dangerous events, so I want to be very specific about when to seek care.

Call 911 immediately for: chest pain that’s severe or doesn’t go away in a few minutes, severe shortness of breath at rest, fainting or near-fainting, sustained palpitations lasting more than a few minutes, or an ICD shock. Don’t drive yourself, don’t wait it out, call.

Call my office the same day for: new palpitations that come and go, lightheadedness that’s new for you, worsening exercise tolerance, new swelling in the legs or ankles, or any concern that’s gnawing at you. Same-day phone contact catches problems early, when they’re easier to fix.

Schedule a clinic visit within a week or two for: questions about medications, side effects that are bothersome but not dangerous, questions about lifestyle (diet, exercise, travel, work), questions about the surveillance schedule, or anything else you want to talk through.

Common Patient Questions

Could I have cardiac sarcoidosis without lung sarcoidosis?

Yes. About a quarter of patients with cardiac sarcoidosis have isolated cardiac disease at the time of diagnosis. They have no obvious lung, eye, skin, or lymph node involvement. The workup still includes a careful search for sarcoidosis in other organs (chest CT, eye exam, skin exam, sometimes a whole-body PET), but in some patients the only organ affected is the heart. Endomyocardial biopsy is sometimes used in these isolated cases when the diagnosis is uncertain after the non-invasive workup.

Why am I being asked to do a special diet before my PET scan?

The diet is the most important pre-scan step for cardiac PET imaging. PET uses radioactive sugar as the tracer, and your heart muscle normally burns sugar for energy, which would make the whole heart light up and hide any patches of inflammation. The 24-hour high-fat, low-carbohydrate, no-sugar diet plus an overnight fast shifts your heart’s metabolism from sugar to fat. With normal heart muscle running on fat, the inflammatory patches (which still use sugar) show up clearly. If the diet isn’t followed strictly, the scan can be uninterpretable and we may have to repeat it.

Will I be on prednisone for the rest of my life?

Probably not. The typical initial course runs 6 to 12 months at progressively lower doses. After the inflammation is quiet on the PET scan and your symptoms have stabilized, the steroid is tapered slowly. Some patients can be tapered off completely. Others need a low maintenance dose (5 to 10 milligrams of prednisone) plus a steroid-sparing medication like methotrexate to keep the disease suppressed. The plan is individualized based on how your disease behaves over time.

If my pacemaker is for sarcoidosis, do I really need a defibrillator too?

Most likely yes. The 2014 Heart Rhythm Society guidelines recommend implanting a device that can defibrillate (an ICD or CRT-D) in most cardiac sarcoidosis patients who need pacing. That’s because the granulomas that disrupted your heart’s wiring are usually accompanied by other granulomas in the heart muscle that can set up dangerous fast rhythms, ones a plain pacemaker can’t stop. The exact device choice depends on your ejection fraction, MRI findings, electrophysiology study results, and individual risk factors, but the default is to include defibrillation capability.

Can cardiac sarcoidosis go into remission?

Yes, in many cases. Active inflammation can be suppressed with steroids and other medications, and the heart can stay stable for years or even decades. Some patients have a single episode that responds to a year of treatment and never relapses. Others have a relapsing-remitting pattern where the disease flares periodically and needs treatment escalation. Imaging surveillance with periodic cardiac MRI and PET helps identify relapses early, before they cause new damage.

Is sarcoidosis hereditary?

There’s a familial component to sarcoidosis in general, with first-degree relatives at slightly increased risk. The genetics are complex, no single gene predicts who gets it. Cardiac sarcoidosis itself doesn’t have established screening recommendations for asymptomatic relatives. If a relative develops symptoms suggestive of sarcoidosis (chronic cough, unexplained shortness of breath, eye inflammation, skin lesions, palpitations, syncope), they should get evaluated like anyone else with those symptoms, with the family history factored into the pretest probability.

Can I exercise with cardiac sarcoidosis?

In most cases, yes. Patients with stable cardiac sarcoidosis, normal or near-normal pumping function, and no significant arrhythmia history can usually do moderate aerobic exercise. Patients with active inflammation, recent VT, or significant pumping reduction need a more conservative approach. Cardiac rehabilitation is a useful structured setting for returning to exercise after the diagnosis. The threshold for restricting activity is set by your cardiologist based on your individual situation, not by a blanket rule for the disease as a whole.

What’s the difference between cardiac sarcoidosis and other diseases that infiltrate the heart?

Cardiac sarcoidosis is one of several infiltrative diseases that can affect the heart muscle. Others include:

Each of these has a distinct pattern on cardiac MRI, distinct blood test findings, and distinct treatments. Cardiac MRI with late gadolinium enhancement is the imaging test that most reliably sorts among them.

What’s the long-term outlook?

It depends a lot on how early the diagnosis is made and how completely the inflammation is treated. Patients with isolated heart block, normal pumping, and minimal scar on MRI usually do very well, often with a long stable course. Patients with badly reduced pumping, extensive scar burden, or recurrent ventricular arrhythmias have a tougher trajectory. Five-year survival across published series ranges from 60 to 90 percent depending on how the patients in the study presented. The single biggest predictor of long-term outcome is probably how early the diagnosis was caught.

Can I have a baby if I have cardiac sarcoidosis?

In many cases yes, but pregnancy with cardiac sarcoidosis is a high-risk pregnancy that needs careful planning with a maternal-fetal medicine specialist alongside your cardiologist. Some sarcoidosis medications (methotrexate, mycophenolate, ACE inhibitors, ARBs like valsartan) are contraindicated in pregnancy and need to be stopped or swapped well before conception. Prednisone is generally considered safe in pregnancy at reasonable doses. Pumping function and arrhythmia risk should be optimized before pregnancy. Talk to your cardiologist if pregnancy is on the table, ideally several months ahead of when you’d want to start trying.

A Final Note From Me

Cardiac sarcoidosis is one of those diagnoses that rewards pattern recognition. Once you’ve seen a few cases, the pattern stands out: a younger patient with heart block that doesn’t fit a coronary story, a non-ischemic cardiomyopathy with a thinned upper septum, a VT substrate in someone whose heart looks too normal on the first echo. These patterns should trigger the workup, because the alternative is missed disease that quietly progresses for years.

If you’ve been given a cardiac sarcoidosis diagnosis, the most important things you can do are: get on appropriate immunosuppression before the inflammation scars more muscle, get the right device when the electrical or rhythm problem warrants it, and stay engaged with the surveillance imaging and clinic follow-up. Patients who do those three things consistently often do remarkably well. The disease can be stabilized for years. Treatments have gotten better over the last decade. And the long-term outlook for an early-diagnosed, well-treated cardiac sarcoidosis patient is dramatically better than the outlook for someone whose diagnosis was missed and who shows up years later in advanced heart failure or after a cardiac arrest.

If you have a younger family member or friend with new heart block, unexplained palpitations or syncope, or a heart failure picture that doesn’t add up, the question of cardiac sarcoidosis deserves to be raised explicitly. Most cardiologists are familiar with the diagnosis. The workup is straightforward once it’s on the radar. The patients I worry about are the ones whose pacemaker went in without a sarcoidosis evaluation. The patients I’m hopeful about are the ones who got the right diagnosis and the right treatment plan early in their course.

References

  1. Birnie, David H., William H. Sauer, Frank Bogun, et al. “HRS Expert Consensus Statement on the Diagnosis and Management of Arrhythmias Associated with Cardiac Sarcoidosis.” Heart Rhythm 11, no. 7 (2014): 1305-1323.

  2. Crouser, Elliott D., Lisa A. Maier, Kevin C. Wilson, et al. “Diagnosis and Detection of Sarcoidosis: An Official American Thoracic Society Clinical Practice Guideline.” American Journal of Respiratory and Critical Care Medicine 201, no. 8 (2020): e26-e51.

  3. Chen, Eugene S., and David R. Moller. “Cardiac Sarcoidosis.” Clinics in Chest Medicine 36, no. 4 (2015): 657-668.

  4. Yazaki, Yoshikazu, Morie Sekiguchi, Toshio Naito, et al. “Comparison of Clinical Features and Prognosis of Cardiac Sarcoidosis and Idiopathic Dilated Cardiomyopathy.” American Journal of Cardiology 88, no. 9 (2001): 1006-1010.

  5. Kandolin, Riina, Jukka Lehtonen, Jukka Airaksinen, et al. “Cardiac Sarcoidosis: Epidemiology, Characteristics, and Outcome over 25 Years in a Nationwide Study.” Circulation 131, no. 7 (2015): 624-632.

  6. Sadek, Mouhannad M., Tracy Yung, Andrew C. T. Ha, et al. “Corticosteroid Therapy for Cardiac Sarcoidosis: A Systematic Review.” Canadian Journal of Cardiology 29, no. 9 (2013): 1034-1041.

  7. Blankstein, Ron, Marcio Sommer Bittencourt, Ross M. Kirschner, et al. “Cardiac Positron Emission Tomography Enhances Prognostic Assessments of Patients with Suspected Cardiac Sarcoidosis.” Journal of the American College of Cardiology 63, no. 4 (2014): 329-336.

  8. Hulten, Edward, Stephanie Aslam, Michael Osborne, Siddique Abbasi, Marcio Sommer Bittencourt, and Ron Blankstein. “Cardiac Sarcoidosis: State of the Art Review.” Cardiovascular Diagnosis and Therapy 6, no. 1 (2016): 50-63.

  9. Greulich, Simon, Christof Sebastian Deluigi, Stefanie Gloekler, et al. “CMR Imaging Predicts Death and Other Adverse Events in Suspected Cardiac Sarcoidosis.” JACC: Cardiovascular Imaging 6, no. 4 (2013): 501-511.

  10. Ribeiro Neto, Manuel L., Gosta B. Pettersson, Carmela D. Tan, Nathaniel L. Smedira, and Daniel A. Culver. “Heart Transplantation in Patients with Cardiac Sarcoidosis.” Journal of Heart and Lung Transplantation 41, no. 6 (2022): 727-734.

  11. Skali, Hicham, Allison R. Schulman, and Sharmila Dorbala. “18F-FDG PET/CT for the Assessment of Myocardial Sarcoidosis.” Current Cardiology Reports 15, no. 4 (2013): 352.

  12. Kron, Jordana, William Sauer, Joel Schuller, et al. “Efficacy and Safety of Implantable Cardiac Defibrillators for Treatment of Ventricular Arrhythmias in Patients with Cardiac Sarcoidosis.” Europace 15, no. 3 (2013): 347-354.