Cardiac amyloidosis
Cardiac amyloidosis is myocardial infiltration by misfolded amyloid fibrils, chiefly transthyretin (ATTR) or light-chain (AL) type, causing a restrictive, thick-walled cardiomyopathy with heart failure, conduction disease, and low-voltage ECG despite increased wall thickness. Diagnosis distinguishes AL (light chains plus biopsy) from ATTR (a positive bone-tracer scan without a plasma cell disorder), and treatment is type-specific plus supportive heart-failure care.
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What this article covers
- Overview
Definition: cardiac amyloidosis is infiltration of the myocardium by misfolded amyloid fibrils, most often transthyretin (ATTR) or immunoglobulin light-chain (AL) protein.
- Epidemiology
ATTR: wild-type ATTR affects older adults (especially men) and is an underrecognized cause of heart failure with preserved ejection fraction; hereditary ATTR has geographic and ancestral clusters.
- Risk factors
Older age and male sex for wild-type ATTR.
- Pathophysiology
Fibril deposition: misfolded transthyretin or light chains deposit in the myocardial interstitium.
- Clinical features
Heart failure with preserved ejection fraction: dyspnea, edema, and right-sided congestion.
- Differential diagnosis
Hypertensive heart disease and hypertrophic cardiomyopathy: true myocyte hypertrophy with high or normal QRS voltage, distinguished from amyloid by the absence of voltage-mass mismatch and negative…
- Diagnosis
Establish by confirming amyloid and typing it, excluding AL before diagnosing ATTR noninvasively: the diagnostic basis is recognizing the phenotype (thick walls with low ECG voltage and restrictive…
- Management
First-line, type-specific therapy: for ATTR, a transthyretin stabilizer (tafamidis 61 mg PO daily) improves outcomes; for AL, urgent plasma-cell-directed chemotherapy (for example a bortezomib-based regimen) with hematology.
- Complications
Progressive heart failure and low-output state.
- Prognosis
AL: poor without prompt treatment, especially with advanced cardiac involvement.
- Prevention
Early recognition of the phenotype (voltage-mass mismatch, unexplained HFpEF, carpal tunnel) enables timely treatment.
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Related articles
- Restrictive cardiomyopathy
Restrictive cardiomyopathy is impaired ventricular filling from a stiff, noncompliant myocardium with preserved (or near-preserved) systolic function and non-dilated ventricles, most often from infiltration such as amyloidosis. It presents as predominantly right-sided heart failure, and diagnosis centers on echocardiography and cardiac MRI plus a search for the underlying cause, distinguishing it from constrictive pericarditis; management treats the underlying cause with cautious diuresis.
- Heart failure
Heart failure is a clinical syndrome of impaired cardiac filling or ejection causing congestion and reduced perfusion, classified by ejection fraction. Diagnosis integrates symptoms, signs, natriuretic peptides, and echocardiography, and treatment of reduced-ejection-fraction disease is quadruple guideline-directed therapy, with device therapy and cause-specific management.
- Hypertrophic cardiomyopathy
Hypertrophic cardiomyopathy is an autosomal dominant sarcomere disease causing unexplained left ventricular hypertrophy, often with dynamic left ventricular outflow tract obstruction, and is a leading cause of sudden cardiac death in young people. Diagnosis is by echocardiography or cardiac MRI showing unexplained hypertrophy, and management includes negative inotropes, obstruction relief, and ICD placement for high sudden-death risk.
- Constrictive pericarditis
Constrictive pericarditis is a rigid, often calcified pericardium that impairs diastolic filling, causing predominantly right-sided heart failure. It follows pericardial injury (post-surgical, tuberculous, radiation, or idiopathic), is distinguished from restrictive cardiomyopathy by hemodynamic and imaging features, and definitive treatment is pericardiectomy.