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Restrictive Cardiomyopathy

Practice Essentials

Restrictive cardiomyopathy (RCM) is a rare disease of the myocardium and is the least common of the three clinically recognized and described cardiomyopathies.
It is characterized by diastolic dysfunction with restrictive ventricular physiology, whereas systolic function often remains normal. Atrial enlargement occurs due to impaired ventricular filling during diastole, but the volume and wall thickness of the ventricles are usually normal. RCM accounts for approximately 5% of all cases of diagnosed cardiomyopathies.

Signs and symptoms

Symptoms may include the following:

Gradually worsening shortness of breath

Progressive exercise intolerance

Orthopnea

Fatigue

Weight loss, cardiac cachexia

Paroxysmal nocturnal dyspnea

Abdominal discomfort or liver tenderness

Chest pain, primarily in patients with amyloidosis or due to angina

Palpitations

Physical examination

Search for extracardiac manifestations of a systemic disorder that may cause secondary restrictive cardiomyopathy (eg, hemochromatosis, amyloidosis, sarcoidosis, or scleroderma).

General examination findings:

Increased jugular venous pressure

Decreased pulse volume

Ascites and pitting edema of the lower extremities

Hepatomegaly due to fluid or amyloid infiltration

Easy bruising, periorbital purpura, macroglossia, and other systemic findings (eg, carpal tunnel syndrome) may be evidence of amyloidosis

Cardiovascular system examination findings:

Normal S
1 and S
2 heart sounds, with a normal S
2 split

Loud early diastolic filling sound (S
3)

A fourth heart sound (S
4) is almost never present

Murmurs due to mitral and tricuspid valve regurgitation (usually not hemodynamically significant)

Respiratory system examination findings:

Breath sounds are often decreased due to pleural effusions, frequently bilateral and large in amyloidosis

Crepitations or rales are rarely heard

See Clinical Presentation for more detail.

Diagnosis

Establishing the diagnosis of RCM and excluding constrictive pericarditis are imperative. The workup in a patient with suspected restrictive cardiomyopathy may include the following:

Complete blood cell (CBC) count

Blood gas analysis

Serum electrolyte, blood urea nitrogen (BUN), and creatinine levels

Liver function profile

Serum iron concentrations and other possible indicators of hemochromatosis

Serum brain natriuretic peptide (BNP) levels

Radiography

Angiography

Echocardiography

Cardiac catheterization

Electrocardiography

Radionuclide imaging

Cardiovascular magnetic resonance imaging (CMRI)

Computed tomography (CT) scanning to exclude diagnosis of restriction

Ventricular biopsy

Liver biopsy for diagnosis of hemochromatosis

See Workup for more detail.

Management

RCM has no specific treatment. However, therapies directed at individual causes of RCM have been proven to be effective.

Pharmacologic therapy may include:

Beta blockers

Amiodarone

Cardioselective calcium channel blockers

Diuretics

Anticoagulants for patients with atrial fibrillation

Digoxin (use with caution)

Melphalan (for antiplasma cell therapy in systemic amyloidosis)

Chemotherapy (in amyloidosis)

Corticosteroids, cytotoxic agents (eg, hydroxyurea), and interferon (in Loeffler endocarditis)

Chelation therapy or therapeutic phlebotomy (in hemochromatosis)

Other treatments:

Pacemaker implantation

Endomyocardectomy

Cardiac transplantation

Novel therapies (eg, RNA interference or gene silencing molecules that target abnormal protein production in familial amyloidosis)

See Treatment for more detail.

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