Restrictive Cardiomyopathy

Restrictive cardiomyopathy causes restricted filling and reduced diastolic volume of either or both ventricles, with normal or near-normal wall thickness and systolic function. Although rhythm and pumping remain normal, the restricted filling reduces blood flow, leading ultimately to failure.

There are separate articles which discuss Cardiomyopathies, Hypertrophic Cardiomyopathy, Dilated Cardiomyopathy and Arrhythmogenic Right Ventricular Cardiomyopathy.

• Relatively uncommon and the least common of the cardiomyopathies.
• Can occur in the young, and tends to be progressive.
• Restrictive cardiomyopathy is a leading cause of heart transplantation.
• Familial inheritance is not characteristic of restrictive cardiomyopathy.
• Restrictive cardiomyopathy is more prevalent in tropical Africa than in the Western world.

Restrictive cardiomyopathy is usually caused by endomyocardial fibrosis:

• Idiopathic
• Amyloidosis
• Haemochromatosis
• Sarcoidosis
• Glycogen storage disease
• Scleroderma
• Loffler's eosinophilic endocarditis
• Tropical endomyocardial fibrosis
• Scarring following acute myocardial infarction

• Presents with heart failure but normal systolic function: dyspnoea, fatigue, loud 3rd heart sound, pulmonary oedema, murmurs due to valve incompetence.
• Heart size is usually normal or slightly enlarged.
• Features of right ventricular failure predominate: raised JVP, with prominent x and y descents, hepatomegaly, oedema, ascites.

• Initial investigations as for heart failure with ECG, chest x-ray, blood tests including renal function, electrolytes cardiac enzymes and liver function tests
• Cardiac catheterisation
• Magnetic resonance imaging
• Investigations of possible underlying cause
• Cardiac biopsy may be required to differentiate restrictive cardiomyopathy from constrictive pericarditis and to help identify an underlying cause¹

Apart from constrictive pericarditis which is the main differential diagnosis to consider, other constrictive diseases may mimic restrictive cardiomyopathy, so the following are often considered:

• Metastases
• Carcinoid
• Radiation
• Cardiac tamponade - constrictive only

• Management of heart failure, including diuretics
• Anticoagulants
• Amiodarone: can reduce ventricular arrhythmias in high-risk patients
• Pacemaker may be required (patients are often not able to tolerate the cardiac dysfunction associated with arrhythmias)
• Implantable cardioverter defibrillator: to prevent sudden death in high-risk patients
• Heart transplantation may be required

• Variable depending on underlying cause.
• Restrictive cardiomyopathy due to amyloid has a rapid progression to death.¹