Cardiac Amyloidosis and Sarcoidosis

Why we cover these together

Cardiac amyloidosis and cardiac sarcoidosis are very different diseases. One is caused by misfolded proteins clumping inside the heart muscle. The other is caused by clusters of inflammatory cells, called granulomas, infiltrating the muscle. They have different mechanisms, different treatments, and different long-term outlooks.

What they have in common is what brings patients to our office: they damage both the pumping function and the electrical wiring of the heart at the same time. That combination — heart failure plus abnormal rhythms or conduction problems — is what makes them an electrophysiology issue as much as a heart-failure issue. We’re often part of the team from very early on.

Both diseases were under-recognized for decades and are now being diagnosed much more often, partly because the tests for them have gotten much better and partly because the treatments now exist that make finding them worthwhile.

Cardiac amyloidosis

What is happening in the heart

In amyloidosis, certain proteins in your body misfold — they take on the wrong shape — and instead of being broken down and cleared, they clump together and deposit into tissues. When those deposits build up in the heart muscle, the muscle becomes thickened and stiff. It can still squeeze, but it can no longer relax and fill properly between beats. That’s called restrictive cardiomyopathy, and it eventually causes heart failure even though the squeeze itself may look surprisingly preserved on an echocardiogram.

The two main types

The protein involved determines the type of amyloid and the treatment.

• ATTR amyloidosis (transthyretin amyloid) is the most common kind we see in the heart. The protein involved is transthyretin, made by the liver. It can be the inherited form, where a single genetic change in the TTR gene causes the protein to misfold from an early age, or it can be the wild-type form (formerly called “senile amyloid”), where the normal protein simply becomes unstable with age and starts misfolding in the 70s and 80s. Wild-type ATTR is much more common in older men and is increasingly recognized as a major cause of heart failure with preserved ejection fraction in that population.
• AL amyloidosis (light chain amyloid) is caused by an abnormal population of plasma cells in the bone marrow producing too much of a single immune protein fragment (a “light chain”). Those light chains misfold and deposit into the heart and other organs. AL amyloid is a hematologic cancer-spectrum disorder that needs urgent treatment from a hematologist; the cardiac involvement is the most dangerous feature.

The two types look very similar on imaging but require very different treatments — so distinguishing them is one of the central jobs in workup.

Symptoms

The picture is often subtle and develops over years before being recognized.

• Fatigue and exercise intolerance that develops gradually.
• Shortness of breath with activity, then at rest, then lying flat.
• Swelling in the legs.
• Lightheadedness or fainting, particularly on standing (low blood pressure from a stiff, underfilled heart and from amyloid affecting the nerves that control blood pressure).
• Palpitations or sustained fast heartbeats from atrial fibrillation.
• Slow heart rate or pauses from amyloid infiltrating the AV node and bundle of His.
• A history of bilateral carpal tunnel syndrome, spinal stenosis, or biceps tendon rupture — surprisingly common red flags for ATTR.

How we diagnose it

The workup follows a typical sequence.

• Echocardiogram. Shows a thickened heart muscle with normal or near-normal squeezing, abnormal relaxation, and a characteristic “speckled” or “granular” texture. We also measure a special index called strain — amyloid tends to spare the very tip of the heart, producing a “cherry-on-top” pattern that is highly suggestive.
• Cardiac MRI. Shows thickening plus a distinctive pattern of late gadolinium enhancement (a contrast agent that highlights the abnormal tissue).
• PYP (pyrophosphate) scan. A nuclear medicine study where a radioactive tracer binds to ATTR amyloid deposits. A positive scan in the right clinical setting essentially diagnoses ATTR without a biopsy — a remarkable advance from a decade ago when biopsy was required.
• Blood and urine testing to look for abnormal light chains and rule out AL amyloid before assuming ATTR.
• Genetic testing for the TTR gene, to distinguish inherited from wild-type ATTR.
• Biopsy — either of a directly involved organ (the heart, sometimes the abdominal fat pad) — when AL is suspected or when the picture is unclear.

How we treat it

• For ATTR, tafamidis is the cornerstone — a pill that stabilizes the transthyretin protein so it doesn’t misfold. It slows progression and improves survival. Newer medications that silence the production of TTR by the liver (patisiran, vutrisiran, inotersen) are now available and reduce protein levels even more aggressively. These drugs have transformed an “untreatable” disease into a manageable chronic condition.
• For AL amyloid, hematology drives treatment with chemotherapy and sometimes stem cell transplant aimed at the abnormal plasma cells. The cardiologist’s role is supportive — careful diuretic management, controlling arrhythmias, watching for sudden deterioration.
• General heart-failure care matters for both — but with a few important twists. Beta-blockers, ACE inhibitors, and ARBs are often poorly tolerated because the stiff amyloid heart depends on a brisk heart rate and good filling pressures. We dose them very carefully and sometimes can’t use them at all.
• Anticoagulation is started in most amyloid patients with atrial fibrillation regardless of CHA₂DS₂-VASc, because the stiff amyloid atria form clots even between AFib episodes.

What an electrophysiologist watches for

This is where my role overlaps most with the rest of the cardiology team.

• AV block. Amyloid infiltrates the AV node and the bundle of His, and many patients eventually need a pacemaker. We often watch for this early — a slow resting heart rate, a borderline PR interval, or a long pause caught on a monitor can be enough to plan ahead.
• Atrial fibrillation. Common, often poorly tolerated (because the stiff atria can’t compensate for the loss of atrial kick). Rate-control medications are tricky for the reasons above; rhythm control with cardioversion and antiarrhythmics is often preferred. Ablation is reasonable in selected patients but harder than usual.
• Ventricular arrhythmias. Less common than in sarcoidosis but they do occur. The decision about a defibrillator in advanced amyloid is individualized — life expectancy and quality-of-life considerations weigh heavily.

Cardiac sarcoidosis

What is happening in the heart

Sarcoidosis is an inflammatory disease in which the immune system forms clusters of cells called granulomas that infiltrate tissues. It is best known as a lung disease, but it can involve almost any organ, and the heart is one of the most clinically important sites of involvement. When granulomas land in the heart muscle they create patchy areas of inflammation and scarring — and that patchy scarring is what causes the electrical problems and pumping problems we see.

Symptoms

Cardiac sarcoidosis is famous for being silent until it isn’t. Many patients are diagnosed only after a dramatic first presentation.

• Heart block. A patient under 60 — or even under 40 — who comes in with sudden-onset complete heart block is one of the most classic presentations. Cardiac sarcoid should always be considered in a younger patient who has heart block without an obvious cause.
• Ventricular tachycardia or cardiac arrest. Sudden, dangerous fast rhythms from the lower chambers are common, sometimes as the first symptom.
• Heart failure when the patchy scarring is extensive enough to weaken the squeeze.
• Palpitations, chest discomfort, shortness of breath, lightheadedness.
• A history of pulmonary sarcoidosis in roughly half of patients — but heart involvement can also occur on its own, without any previous diagnosis.

How we diagnose it

This is one of the harder diagnoses in cardiology because there is no single perfect test.

• Cardiac MRI is usually the first imaging step — it shows patchy areas of late gadolinium enhancement that suggest scar, often in a distinctive distribution involving the septum and the basal walls.
• FDG-PET scan identifies areas of active inflammation. A patient is prepared with a special low-carbohydrate diet for 12–24 hours so that the heart muscle stops using glucose for fuel; any “hot spots” of glucose uptake on the resulting scan then represent inflammation (or sometimes cancer). The combination of MRI scar plus PET inflammation is a strong picture for cardiac sarcoid.
• Endomyocardial biopsy can confirm granulomas, but the disease is patchy and biopsies frequently miss it — a negative biopsy doesn’t rule out the disease.
• Lymph node biopsy of any abnormal-looking lymph nodes elsewhere in the body (often in the chest) can confirm sarcoid without sampling the heart.
• Holter or implantable loop recorder to catch the arrhythmias that drive much of the management.

How we treat it

• Immune-suppressing therapy. This is the foundation. Prednisone is started in most patients with active inflammation on imaging, and steroid-sparing agents (methotrexate, azathioprine, sometimes biologics like infliximab) are added once the disease is controlled so that long-term steroid exposure can be minimized.
• Heart failure therapy when the squeeze is reduced, using the standard combination of beta-blocker, ACE inhibitor or ARB, an aldosterone antagonist, and an SGLT2 inhibitor.
• Implantable cardioverter-defibrillator (ICD) for many patients, because the risk of sudden cardiac death is high. The threshold for an ICD is lower in cardiac sarcoid than in many other conditions — we often recommend one even when the ejection fraction looks acceptable, because the scar burden tells a bigger story than the squeeze does.
• Pacemaker for patients with significant heart block, often as part of the ICD system rather than a standalone pacemaker.
• Catheter ablation for ventricular tachycardia that breaks through medical and ICD therapy. VT in sarcoid is scar-mediated and behaves like VT after a heart attack — it lives at the edges of the scar, and mapping-guided ablation can be highly effective.

What an electrophysiologist watches for

• Unexplained AV block in a younger patient — sarcoid until proven otherwise.
• Recurrent VT that doesn’t respond well to standard treatment.
• Decisions about an ICD. We are often the team weighing whether the scar pattern, ejection fraction, and history together warrant an implant.
• Coordination with rheumatology or pulmonology managing the immunosuppression. Steroid bursts can make arrhythmias quiet temporarily, which sometimes confuses the picture about whether they are truly controlled.

Why we see these patients together

The reason a single page covers two diseases that aren’t biologically related is practical: both diseases sit at the intersection of cardiomyopathy and electrophysiology. Both produce a combination of pumping dysfunction and electrical instability that is unusual in cardiology. A patient with one of these conditions almost always benefits from being followed by both a cardiomyopathy or heart-failure specialist and an electrophysiologist, working from the same imaging and the same monitoring data.

Both diseases are also areas where the diagnostic and therapeutic landscape has changed dramatically in the last ten years. ATTR amyloid went from a fatal condition with no treatment to one where survival has been doubled by a single pill. Sarcoidosis is being recognized at far earlier stages thanks to MRI and PET. And both diseases now make extensive use of EP procedures — pacemakers, defibrillators, ablations — that we can offer at the right point in the course.

What to expect at your visit

If you’ve been told you might have cardiac amyloid or cardiac sarcoid, or you’ve already been diagnosed, here’s roughly what an EP visit looks like in this setting.

We’ll spend time on the story — when symptoms began, how they’ve progressed, family history, other organs involved, what testing you’ve already had. We’ll review your ECG, your echo, your MRI, and any nuclear scans carefully. We’ll talk about the specific arrhythmia issues that matter for your form of the disease — whether you’re at risk of slow heartbeats, fast heartbeats from the upper chambers, or fast heartbeats from the lower chambers — and we’ll decide together whether you need additional monitoring, an EP study, a pacemaker, a defibrillator, or any of the procedures we discuss elsewhere in this library.

Most patients don’t need everything. But the value of being seen specifically for the electrical side of these diseases is that we can plan ahead — catching a slow rhythm before it causes a fall, identifying high VT risk before it becomes a cardiac arrest, choosing the right device when the time comes — rather than reacting after something has gone wrong.