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For further information, see CMDT Part 10-47: Restrictive Cardiomyopathy

Key Features

  • Right heart failure tends to dominate over left heart failure

  • Pulmonary hypertension is present

  • Amyloidosis is the most common cause

  • Echocardiography is key to diagnosis

    • Rapid early filling is present with diastolic dysfunction

    • Normal or near normal ejection fraction (EF) with normal size left ventricle (LV)

  • MRI and cardiac catheterization are helpful

  • Radionuclide imaging or myocardial biopsy can confirm amyloid

Clinical Findings

  • Symptoms may include angina, syncope, stroke and peripheral neuropathy

  • Characterized by impaired diastolic filling with reasonably preserved contractile function

  • In Africa, endomyocardial fibrosis is seen

  • Other causes of restrictive cardiomyopathy

    • Infiltrative cardiomyopathies (eg, hemochromatosis, sarcoidosis)

    • Connective tissue diseases (eg, scleroderma)

  • Restrictive cardiomyopathy must be distinguished from constrictive pericarditis

Diagnosis

  • ECG

    • Conduction disturbances are frequently present

    • Low voltage on the ECG combined with ventricular hypertrophy on the echocardiogram is suggestive of disease

  • Echocardiogram reveals

    • A small thickened LV with bright myocardium (speckled)

    • Rapid early diastolic filling revealed by the mitral inflow Doppler

    • Biatrial enlargement

    • LV chamber size is usually normal with a reduced LVEF

    • Atrial septal thickening

  • Technetium pyrophosphate imaging (bone scan imaging)

    • Can identify amyloid deposition in the myocardium

    • Has become the noninvasive imaging modality of choice for diagnosing transthyretin amyloidosis

  • With typical scintigraphic findings in patients without a monoclonal gammopathy, biopsy is no longer necessary for diagnosis

  • Cardiac MRI presents a distinctive pattern of diffuse hyperenhancement of the gadolinium image in amyloidosis

  • Rectal, abdominal fat, or gingival biopsies can confirm systemic involvement

  • Endomyocardial biopsy is required to confirm that cardiac amyloid is present

  • Mass spectroscopy is recommended on all tissue in question

  • TTR gene sequencing is recommended in patients in whom the TTR wild type or TTR mutant variant is suspected

Treatment

  • Tafamidis

    • Treatment of choice for transthyretin amyloidosis cardiomyopathy

    • Results from the Transthyretin Amyloidosis Cardiomyopathy Clinical Trial (ATTR-ACT) showed

      • Substantially improved survival

      • Reduced hospitalization

      • Improved quality of life for patients with transthyretin amyloidosis cardiomyopathy

  • Diuretics can help, but excessive diuresis can produce worsening kidney dysfunction

  • Loop diuretics, thiazides, and aldosterone antagonists are all useful

  • Ultrafiltration devices allow for improved diuresis

  • β-Blockers help slow heart rates and improve filling

  • Corticosteroids

    • May be helpful in sarcoidosis

    • More effective for the conduction abnormalities than the heart failure

  • In amyloidosis, treatment depends on the type of amyloid protein and extent of disease

    • First-line treatment for AL amyloidosis includes alkylator-based chemotherapy or high-dose melphalan followed by autologous stem cell transplantation

    • In familial amyloidosis with transthyretin deposition, liver transplantation may be an option

    • Cardiac transplantation has been used in primary cardiac amyloidosis and no evidence for systemic involvement

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