Heart & vascular pathology
Cardiomyopathy
Idiopathic restrictive cardiomyopathy
Author: Saranya Singaravel, M.B.B.S.
Last author update: 1 November 2016
Last staff update: 9 May 2023
Copyright: 2016-2024, PathologyOutlines.com, Inc.
PubMed Search: idiopathic restrictive cardiomyopathy
Table of Contents
Definition / general | Essential features | Terminology | Epidemiology | Pathophysiology | Etiology | Clinical features | Diagnosis | Laboratory | Radiology description | Radiology images | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Electron microscopy description | Differential diagnosis | Additional referencesCite this page: Singaravel S. Idiopathic restrictive cardiomyopathy. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/heartidiopathicrestrictive.html. Accessed December 18th, 2024.
Definition / general
- Rare heart muscle disease with altered hemodynamic pattern and myocardial compliance, resulting in a restrictive filling pattern and diastolic ventricular dysfunction with normal or near normal systolic function and ventricular wall thickness
- Abnormal morphology may or may not be present
- It is a diagnosis of exclusion and no evidence of infiltrative, pericardial or endocardial disease should be present
- Accounts for 3% - 5% of cardiomyopathies
Essential features
- Restrictive filling pattern
- Mutations in sarcomeric protein genes
- Diagnosis of exclusion
Terminology
- Also known as primary restrictive cardiomyopathy
Epidemiology
- Restrictive cardiomyopathy is the least common type of cardiomyopathy
- Exact prevalence is not known
- Slightly more common in women (F:M ratio, 1.5:1)
- More common in adults but can occur in any age group
- Prognosis is particularly poor in children and two year survival is less than 50%
Pathophysiology
- Mutations in sarcomeric proteins such as cTnI (a troponin subunit) increase the Ca2+ sensitivity of cardiac myofilaments, increasing the contractility and producing diastolic dysfunction
Etiology
- Etiology of primary restrictive cardiomyopathy is not clear
- Mutations have been identified in the sarcomeric protein genes such as cardiac troponin I, troponin T2, beta myosin heavy chain and alpha cardiac actin
- Autosomal dominant inheritance pattern is seen
- Familial cases have been documented
- Cases of restrictive and hypertrophic cardiomyopathy have been seen in the same family and may represent 2 different phenotypes of the same basic sarcomeric disease
- Mutations in the desmin gene have also been identified - restrictive phenotype is typically accompanied by atrioventricular blocks
Clinical features
- Most common presentation is congestive heart failure and patients may require transplantation
- Atrial fibrillation is very common; also elevated systemic and pulmonary venous pressures
- Jugular venous pressure may be increased
- Left ventricular impulse is usually normal and palpable
- Third heart sound may be audible due to rapid ventricular filling
- Systolic murmurs of mitral and tricuspid regurgitation may also be auscultated
Diagnosis
- Diagnostic right and left heart catheterization is an important diagnostic modality
- Pressures in all the chambers and cardiac output are measured according to the Fick method
- Dip plateau morphology in the LV diastolic pressure tracing is characteristic
- ECG is invariably abnormal but is nonspecific
- Predominant rhythm is atrial fibrillation with premature beats and conduction delay
- QRS voltage is normal
Laboratory
- Diagnosis can be established on right ventricular endomyocardial biopsy
- One biopsy fragment may be fixed in glutaraldehyde for electron microscopic evaluation
Radiology description
- Biatrial enlargement with pulmonary venous congestion and pleural effusions
Radiology images
Images hosted on other servers:
Echocardiographic morphological
features typical of idiopathic RCM
Case reports
- Report of seven cases (PDF file - Acta Pediátr Mex 2014;35:87)
Treatment
- Heart failure is managed medically
- In cases with atrial fibrillation, antiarrythmics are useful
- In severe cases, heart transplant may be considered
Gross description
- Gross examination of the heart shows biatrial dilatation due to increased filling pressures
- Ventricles are relatively normal sized
- Ventricular cavity is normal
- Ventricular wall is abnormal, with a rubbery texture
- Thickening of the endocardium may be observed
Gross images
Images hosted on other servers:
men demonstrating
prominent biatrial
enlargement
Microscopic (histologic) description
- Microscopic changes are nonspecific and include myocyte hypertrophy, focal or diffuse perimyocytic fibrosis and focal myofiber disarray
Microscopic (histologic) images
Images hosted on other servers:
microscopy
showing marked
interstitial fibrosis
Positive stains
- Masson's trichrome may be useful to demonstrate the perimyocytic fibrosis
Electron microscopy description
- Diffuse fibrosis of the perimyocyte produces a characteristic lattice of collagen surrounding every myocyte
- Patients with desmin cardiomyopathy show granulofilamentous intracytoplasmic material
Differential diagnosis
- Constrictive pericarditis (J Am Coll Cardiol 2016;67:2061)
- Obliterative endomyocardial disease
- Specific cardiomyopathies such as amyloidosis and hemochromatosis
Additional references
