Cardiomyopathy
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Cardiomyopathy, abbreviated as CM, is a domain of cardiology and forensic pathology -- as it many cardiomyopathies can lead to sudden death.
Overview
Types[1]
- Dilated cardiomyopathy - most common ~ 90%
- Hypertrophic cardiomyopathy
- Restrictive cardiomyopathy - least common
Note: The frequency of the CMs is in alphabetic order dilated, hypertrophic, restrictive.
Dilated cardiomyopathy
General
- Classic cause of sudden death in young athletes.[2]
- Most common of the cardiomyopathies.
Causes:
- Myocarditis - leading cause, usually viral.[3]
- Familial ~ 30% - can be AD with variable penetrance, AR, X-linked.
Microscopic
Features:
- Epicardial fibrosis.
- Usually non-specific.
Hypertrophic cardiomyopathy
General
- Abbreviated HCM.
Microscopic
Features:[4]
- Myocardial fibre has increased transverse size (40 micrometres).
- Normal myocardial fibre width = 15 micrometres.
- Interstitial fibrosis.
Hypertrophic obstructive cardiomyopathy
- Considered to be a variant of HCM.
Arrhythmogenic right ventricular cardiomyopathy
General
- Previously known as "arrhythmogenic right ventricular dysplasia".
- Associated with sudden cardiac death in "young people".[5]
- Male > female.
Etiology
- Genetic - mutations in:
- Desmosomal proteins, especially plakoglobin and desmoplakin.
- Usually autosomal dominant.
- Autosomal recessive variant: Naxos syndrome.[6]
- Clinical: wooly hair, palmar & plantar keratoses.
Histology
Features:[7]
- "Moth-eaten" appearance:
- Loss of myocytes, replaced by:
- Fat and/or
- Scar tissue.
- Loss of myocytes, replaced by:
- +/-Inflammation (lymphocytes, macrophages).
- Myocytes have "bubbly" appearance with loss of myofibres and cross-striations.
Image:
Gross features
Gross:[7]
- RV wall thinning/replacement with fat.
- Especially fat where fat is not usually seen - posterior RV wall, RVOT.
- Septum usually has relative sparing
- Thus, endomyocardial biopsy is not reliable.
- +/-Aneurysms/dilation.
See also
- Heart.
- Cardiac sarcoidosis.
- Amyloidosis - covers cardiac amyloidosis.
References
- ↑ Robbins p.601.
- ↑ Gojanovic B, Feihl F, Gremion G, Waeber B (February 2007). "[Sudden death in young athletes]" (in German). Praxis (Bern 1994) 96 (6): 189-98. PMID 17330410.
- ↑ Dilated cardiomyopathy: a review. Luk A, Ahn E, Soor GS, Butany J. J Clin Pathol. 2009 Mar;62(3):219-25. Epub 2008 Nov 18. Review. PMID 19017683. http://jcp.bmjjournals.com/cgi/content/full/62/3/219
- ↑ Robbins pp.601-3.
- ↑ Sudden cardiac death due to hypertrophic cardiomyopathy can be reduced by pre-participation cardiovascular screening in young athletes. URL: http://eurheartj.oxfordjournals.org/cgi/content/full/27/18/2152. Accessed on: 16 December 2009.
- ↑ http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=601214
- ↑ 7.0 7.1 URL: http://emedicine.medscape.com/article/1612324-overview