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, Dilated Cardiomyopathies and Arrhythmogenic Right Ventricular Cardiomyopathy.

Epidemiology

• Relatively uncommon and the least common of the cardiomyopathies.
• Most patients are elderly.¹
• 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.

Causes

Restrictive cardiomyopathy is usually caused by endomyocardial fibrosis:

• Idiopathic
• Amyloidosis²
• Haemochromatosis
• Sarcoidosis
• Glycogen storage disease
• Scleroderma
• Löffler's eosinophilic endocarditis
• Tropical endomyocardial fibrosis
• Scarring following acute myocardial infarction

Presentation

• 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.

Investigations

• Initial investigations as for heart failure with ECG, chest X-ray, blood tests including renal function, electrolytes, cardiac enzymes and liver function tests
• Brain natriuretic peptide (BNP) levels are significantly elevated in restrictive cardiomyopathy compared with constrictive pericarditis patients; BNP can be a useful noninvasive marker for the differentiation of the two conditions.³
• Echocardiography - thickened ventricular walls, valves and atrial septum with small cavities¹
• 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 cause^4,5

Differential diagnosis

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

• 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 ⁶
• Transplantation is indicated for patients who do not have aggressive myeloma

Prognosis

• Variable, depending on the underlying cause.
• Restrictive cardiomyopathy due to amyloid has a rapid progression to death with patients dying less than a year after diagnosis.⁴

Document references

1. Oakley C; Aetiology, diagnosis, investigation, and management of the cardiomyopathies. BMJ. 1997 Dec 6;315(7121):1520-4.
2. Desai HV, Aronow WS, Peterson SJ, et al; Cardiac amyloidosis: approaches to diagnosis and management. Cardiol Rev. 2010 Jan-Feb;18(1):1-11. [abstract]
3. Leya FS, Arab D, Joyal D, et al; The efficacy of brain natriuretic peptide levels in differentiating constrictive J Am Coll Cardiol. 2005 Jun 7;45(11):1900-2. [abstract]
4. Franz WM, Muller OJ, Katus HA; Cardiomyopathies: from genetics to the prospect of treatment. Lancet. 2001 Nov 10;358(9293):1627-37. [abstract]
5. The Role of Endomyocardial Biopsy in the Management of Cardiovascular Disease, European Society of Cardiology (2007)
6. Maron BJ; Can sudden cardiac death be prevented? Cardiovasc Pathol. 2010 Apr 7. [abstract]

Internet and further reading

• Goswami G; Restrictive cardiomyopathy, eMedicine, Oct 2008.
• The Cardiomyopathy Association; Homepage.

Acknowledgements