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Overview
What Is Cardiac Amyloidosis?
Cardiac amyloidosis is a condition in which abnormal amyloid proteins build up in the heart muscle. These deposits can make the heart stiff, reducing its ability to relax and fill with blood and, in some cases, to pump effectively. The two main types are AL amyloidosis, caused by abnormal light-chain proteins, and ATTR amyloidosis, caused by misfolded transthyretin. This amyloidosis definition is important because each type affects people differently and needs different treatment.
Symptoms
Cardiac Amyloidosis Symptoms
Amyloidosis symptoms may develop gradually and can resemble other heart conditions. Cardiac amyloidosis symptoms vary according to the amyloid type, how much the heart is affected and whether other organs are involved. Some people first notice problems with exercise, breathing, fluid balance or heart rhythm.
- Shortness of breath may occur during activity or when lying down.
- Fatigue and reduced exercise tolerance can result from a heart that cannot fill or pump normally.
- Swelling in the legs, ankles or abdomen may develop as fluid builds up.
- A rapid or irregular heartbeat can cause palpitations or a fluttering sensation.
- Dizziness or fainting may occur when the heart cannot maintain adequate circulation.
- Chest discomfort can occur and should be assessed, especially if it is new or severe.
Causes
What Causes Cardiac Amyloidosis?
AL and ATTR amyloidosis
AL cardiac amyloidosis develops when abnormal plasma cells produce misfolded light-chain proteins that form amyloid deposits. ATTR cardiac amyloidosis develops when transthyretin, a protein made mainly by the liver, becomes unstable and misfolds. Hereditary ATTR results from an inherited transthyretin gene variant, while wild-type ATTR is not inherited and becomes more common with aging. In both forms, amyloidosis in the heart can stiffen the muscle and interfere with normal filling, pumping and electrical activity.
| Type | Protein source | Typical pattern |
|---|---|---|
| AL | Misfolded immunoglobulin light-chain proteins made by abnormal plasma cells | Usually acquired and associated with a plasma-cell disorder; not typically inherited |
| Hereditary ATTR | Misfolded transthyretin caused by a transthyretin gene variant | Inherited; may affect the heart, nerves or other organs |
| Wild-type ATTR | Misfolded normal transthyretin | Not inherited; more often associated with older age and commonly affects the heart |
Risk Factors
Risk Factors for Cardiac Amyloidosis
- Older age is associated particularly with wild-type ATTR cardiac amyloidosis.
- A family history of ATTR amyloidosis or a transthyretin gene variant raises the possibility of hereditary ATTR.
- Male sex is associated with some ATTR patterns, although anyone can develop the condition.
- Plasma-cell disorders, including some blood cancers, are associated with AL amyloidosis.
- Unexplained heart failure with preserved ejection fraction or unusually thickened heart walls can be a clue to cardiac amyloidosis.
- Carpal tunnel syndrome, nerve symptoms or unexplained involvement of several organs may occur before heart disease is recognized.
- Some people develop amyloidosis without an obvious risk factor.
Complications
Complications of Cardiac Amyloidosis
- Restrictive cardiomyopathy can make the heart stiff and limit how much blood it can hold.
- Heart failure may develop as the heart becomes less able to fill or pump.
- Abnormal heart rhythms can cause palpitations, dizziness or fainting.
- Electrical conduction problems may become severe enough to require a pacemaker.
- Blood clots and stroke can occur, particularly with certain irregular rhythms.
- Low blood pressure may result from impaired circulation or difficulty tolerating medicines.
- Kidney dysfunction and progressive involvement of other organs can occur as amyloid disease advances.
SEEK PROMPT CARE
Symptoms can worsen quickly
Worsening breathlessness, fainting, new chest pain, sustained palpitations or rapidly increasing swelling can signal a serious complication. Seek urgent medical assessment if any of these symptoms develop.
Diagnosis
How Is Cardiac Amyloidosis Diagnosed?
Clinicians combine symptoms, medical and family history, a physical examination and several tests because cardiac amyloidosis can resemble other causes of thickened heart muscle or heart failure. Testing assesses heart structure and function, looks for abnormal proteins and helps determine whether other organs are involved. A careful amyloidosis diagnosis must also identify the specific amyloid type.
- An electrocardiogram checks the heart’s electrical activity and may show patterns associated with amyloid involvement.
- An echocardiogram uses ultrasound to assess wall thickness, filling, pumping and valve function.
- Cardiac MRI provides detailed images of the heart muscle and patterns that may support the diagnosis.
- Blood and urine tests look for abnormal light chains and other signs of AL amyloidosis.
- Nuclear imaging can help identify ATTR deposits in the heart when AL amyloidosis has been appropriately excluded.
- Genetic testing may be recommended when hereditary ATTR is possible.
- A biopsy may be needed when noninvasive testing is inconclusive or tissue confirmation and typing are necessary.
Treatment & Management
Cardiac Amyloidosis Treatment and Management
Type-specific treatment
AL amyloidosis is treated under specialist supervision with therapies that target the abnormal plasma cells and reduce light-chain production. ATTR amyloidosis may be treated with medicines that stabilize transthyretin or reduce its production, depending on the person’s type and clinical situation. Supportive care can include carefully selected diuretics, fluid and salt management, treatment of arrhythmias, anticoagulation when indicated, and devices or advanced therapies for selected patients. Some standard heart-failure medicines may not be well tolerated, so medication changes should be guided by a specialist team.
Outlook and Prognosis
Outlook and Prognosis
Cardiac amyloidosis is often chronic and can be progressive, but outcomes have improved with earlier recognition and type-specific therapies. The outlook depends on the amyloid protein, how much the heart is affected, whether other organs are involved and how well treatment works. Regular follow-up helps clinicians adjust treatment and monitor for changes.
| Factor | Why it matters |
|---|---|
| AL versus ATTR type | The underlying protein and available treatments differ, and AL can progress quickly without treatment. |
| Extent of heart involvement | Greater stiffness, reduced pumping or higher strain on the heart can affect symptoms and treatment choices. |
| Other affected organs | Kidney, nerve, digestive or other organ involvement can add complications and influence care. |
| Rhythm or heart-failure complications | Arrhythmias, conduction problems, fluid buildup and low blood pressure can affect daily function and risk. |
| Response to treatment | Reducing abnormal protein production or stabilizing transthyretin may slow further damage and improve management. |
When Should You See a Doctor
When Should You See a Doctor?
- Arrange a medical visit for unexplained shortness of breath or persistent swelling.
- Ask for evaluation if your exercise tolerance is steadily declining without a clear reason.
- Report fainting, recurrent dizziness or new palpitations to a clinician.
- Discuss unexplained thickening of the heart muscle or heart failure with preserved ejection fraction.
- Consider assessment if you have a family history of hereditary ATTR amyloidosis.
- Seek medical advice for symptoms of amyloidosis affecting other organs, such as numbness, tingling or unexplained digestive problems.
EMERGENCY SYMPTOMS
Get immediate medical help
Call emergency services for severe or sudden shortness of breath, chest pain, fainting, confusion, blue lips, signs of stroke or a rapid or irregular heartbeat accompanied by severe symptoms.
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Cardiac Amyloidosis
Cardiology
