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
Weight loss, cardiac cachexia
Paroxysmal nocturnal dyspnea
Abdominal discomfort or liver tenderness
Chest pain, primarily in patients with amyloidosis or due to angina
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:
1 and S
2 heart sounds, with a normal S
Loud early diastolic filling sound (S
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.
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
Cardiovascular magnetic resonance imaging (CMRI)
Computed tomography (CT) scanning to exclude diagnosis of restriction
Liver biopsy for diagnosis of hemochromatosis
See Workup for more detail.
RCM has no specific treatment. However, therapies directed at individual causes of RCM have been proven to be effective.
Pharmacologic therapy may include:
Cardioselective calcium channel blockers
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)
Novel therapies (eg, RNA interference or gene silencing molecules that target abnormal protein production in familial amyloidosis)
See Treatment for more detail.