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Cardiomyopathy

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This protocol provides a brief overview of cardiomyopathy giving a clinically oriented classification system in which heart muscle disorders are grouped according to ventricular morphology and function.

The protocol makes recommendations for clinical investigations and referrals for the infant / child with acute presentation with dilated, hypertropic and restrictive cardiomyopathy or acute myocarditis.

See: " Check list for acute presentation of DCM, HCM, RCM or acute myocarditis" and " Investigations for acute presentation of DCM, HCM, RCM or acute myocarditis" including first and second tier laboratory investigations.

Please note: Check lists should be used as guide and should not supersede clinical judgement

A non acute presentation with dilated, hypertropic and restrictive cardiomyopathy warrants referral to specialist cardiologist to coordinate specific investigations and referrals to Genetic and Metabolic services as indicated.

Cardiomyopathy

Cardiomyopathies are a challenging group of disorders to classify, because of evolving diagnoses and different systems of classification. In this protocol cardiomyopathy, as defined by the Working Group of Myocardial and Pericardial Disease of the European Society of Cardiology (ESC), is: "A myocardial disorder in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality" 1,4. This is a clinically orientated classification system in which heart muscle disorders are grouped according to specific morphology and functional phenoptypes; each phenotype is then subclassified into familial and non familial forms (Figure 1).

Figure 1

Classification table
Taken from European Society of Cardiology classification of primary cardiomyopathies 1 (Elliot, et al., 2008). HCM, hypertrophic cardiomyopathy; DCM, dilated cardiomyopathy; RCM, restrictive cardiomyopathy; ARVC, arrhythmogenic right ventricular cardiomyopathy.

Classification

  1. Dilated cardiomyopathy (DCM)
  2. Hypertrophic cardiomyopathy (HCM)
  3. Restrictive cardiomyopathy (RCM)
  4. Arrhythmogenic right ventricular cardiomyopathy (ARVC): an uncommon form of inheritable heart disease (estimated prevalence 1:5000), involves predominately the right ventricle with progressive replacement of right ventricular myocardium with adipose and fibrous tissue. Can also occur in the left ventricle, producing a DCM phenotype. Familial disease is common with autosomal inheritance and incomplete penetrance. Presentation with arrhythmias and sudden death.1,4. Not dealt with further in this document.
  5. Unclassified cardiomyopathies
    1. Left ventricular non-compaction (LVNC): is characterized by prominent left ventricular trabeculae and deep inter-trabecular recesses ("spongy" appearance of LV) 1,2, LVNC is associated with left ventricular dilatation and systolic dysfunction, which can be transient in neonates. It is not clear whether LVNC is a separate cardiomyopathy, or a congenital or acquired morphological trait shared by many phenotypically distinct cardiomyopathies 1. LVNC occurs in isolation and in association with congenital cardiac disorders, complex cyanotic heart disease and some neuromuscular disorders 1,2. Not dealt with further in this document.
    2. Takotsubo cardiomyopathy (Transient left ventricular apical ballooning syndrome): characterized by transient regional systolic dysfunction involving the left ventricular apex and/or mid-ventricle in the absence of obstructive coronary disease on coronary angiography1. Not dealt with further in this document.

NB: Many HCM / DCM / LV non compaction genes can have overlapping phenotypes in the same family - can present at different ages and with differing presentations - see Cardiomyopathy Tests at Partners Healthcare Personalised Medicine

Refer to Examples of different diseases that cause cardiomyopathies

Dilated Cardiomyopathy (DCM)

Dilated cardiomyopathy is defined as the presence of left ventricular dilatation and left ventricular systolic dysfunction in the absence of abnormal loading conditions (i.e hypertension, valve disease) or coronary artery disease sufficient to cause global systolic impairment. Right ventricular dilation and dysfunction may be present but is not necessary for the diagnosis. DCM may be idiopathic, familial/genetic, viral and/or immune, alcoholic/toxic, or associated with recognized cardiovascular disease in which the degree of myocardial dysfunction is not explained by the abnormal loading conditions or the extent of ischemic damage 4. i.e post myocarditis, familial/genetic, endocrine (acquired DCM),nutritional deficiencies (acquired DCM), ischaemic, tachymyopathy and other miscellaneous causes . See Examples of different diseases that cause cardiomyopathies

Post myocarditis
DCM can occur at a late stage following cardiac infection and inflammation. In contrast to active or fulminant myocarditis, an acute inflammatory disorder of the heart, inflammatory DCM is defined by the presence of chronic inflammatory cells in association with left ventricular dilatation 1.

Histology and / or immunochemistry are needed for diagnosis.

Investigations: refer to Checklist for acute presentation of DCM, HCM, RCM or acute myocarditis and Investigations for acute presentation of DCM, HCM, RCM or acute myocarditis

Familial/Genetic DCM
25% of western populations have evidence for familial disease with predominantly autosomal dominant inheritance. Familial disease should be suspected when there is a family history of premature cardiac death or conduction system disease or skeletal myopathy 1.

Pointers in examination:
Take a family history and suspect if;

  • Family history of heart failure, sudden death, conduction disorders, atrial fibrillation, pacemakers etc, Stroke (embolus from dilated cardiac chambers), muscular dystrophy in the family (problems with getting up from chair, lifting arms above head, mobility etc
  • The genetic differential diagnosis of DCM is wide and there are more than 20 gene candidate for which testing is available. Thus, genetic testing for DCM is not a first tier test.
  • If the cause of DCM remains unexplained or there is a suspicious family history, a referral to clinical genetics is warranted. Screening of first degree relatives may be warranted as well as further genetic testing.
  • If CK is elevated (do total CK and isoenzyme CK-MB) or the neurological exam is abnormal consider neurology consult to find cause of the combined skeletal and cardiac myopathy (eg Becker/Duchenne, Emory Dreifuss syndrome etc).

Investigations: refer to Checklist for acute presentation of DCM, HCM, RCM or acute myocarditis and Investigations for acute presentation of DCM, HCM, RCM or acute myocarditis

Hypertrophic Cardiomyopathy (HCM)

Defined by the presence of increased ventricular wall thickness or mass in the absence of loading conditions ( systemic hypertension, valve disease i.e aortic valve stenosis) sufficient to cause the observed abnormality1. The myocardium has an enhanced contractile state, but diastolic filling is impaired because of abnormal stiffness of the left ventricle. This may lead to left atrial enlargement and pulmonary venous congestion 4. Heterogenous, usually familial disease with autosomal dominant inheritance predominating 1,4. Familial HCM is caused by a variety of mutations encoding contractile proteins of the cardiac sacromere 2, 4. Typical morphological changes include myocyte hypertrophy and disarray surrounding areas of increased loose connective tissue. Associated with arrhythmias and premature sudden death 4.
See  Examples of different diseases that cause cardiomyopathies

Pointers in Examination:

  • It is important to take a family history with specific enquiry about; deaths attributed to heart problems, sudden unexplained deaths, current symptoms in relatives that might suggest significant HCM
  • Try to obtain the death certificate/post-mortem report/ copy of ECHO's etc to verify diagnosis in an affected family member.
  • The absence of a family history does not exclude this as a possible diagnosis. This can be a new mutation, a parent can carry a mutation and be asymptomatic.

Investigations: refer to refer to Checklist for acute presentation of DCM, HCM, RCM or acute myocarditis and Investigations for acute presentation of DCM, HCM, RCM or acute myocarditis.

  • Refer to cardiologist for specific investigation / work up which is likely to include ; Echo, ECG, MRI, Holter and exercise test, Genetic review for syndromes,
  • Genetic testing for familial HCM is available but expensive as there are many genes. This is not a first tier test but DNA can be stored in case testing is undertaken at a later date.
  • If the cause of familial HCM is not found in the proband, consider inpatient genetics referral or refer case to the Cardiac Inherited Disease Group for discussion. Further family screening may be indicated in first degree relatives and genetic testing may be warranted.

Restrictive Cardiomyopathy

Restrictive cardiomyopathy is characterised by restrictive diastolic filling and reduced diastolic volume in either or both ventricles with normal or near-normal systolic function due to excessively stiff ventricular walls often caused by infiltrative disease processes 4. The ventricle remains normal in size and maintains normal contractility, but the atria are enlarged and out of proportion to the ventricles. The exact prevalence unknown but probably the least common type of cardiomyopathy 1, RCM can be difficult to define because restrictive ventricular physiology occurs in a wide range of different pathologies, it may be idiopathic, familial (familial RCM mostly characterized by autosomal dominant inheritance) or result from other systemic disorders (i.e. amyloidosis; sarcoidosis, anthracycline toxicity) 4 .

Pointers in Examination:

  • Take a family history
  • Look for signs of a skeletal myopathy
  • Consider referral to clinical genetics as part of the investigation of cause.

Features suggesting metabolic cardiomyopathies

  • Metabolic cardiomyopathies are most frequently hypertrophic but dilatation frequently accompanies hypertrophy and can be the predominant finding
  • Metabolic cardiomyopathies can be accompanied multi-system disease and a child should be investigated for this. For example; hypotonia may suggest Pompe disease, rhabdomyolysis or hypoglycaemia may suggest a Fatty acid oxidation disorder (FAOD), neutropenia accompanying cardiomyopathy suggests Barth syndrome and liver disease may suggest a respiratory chain defect
  • Prenatal onset
  • If neonatal cardiomyopathy is associated with arrhythmia this is highly suggestive of a metabolic cause such as a long chain fatty acid oxidation defect. The metabolic consultant on call should be contacted immediately
  • Mode of inheritance is generally autosomal recessive however an X-linked pattern may suggest Barth syndrome, Fabry and Hunter disease and maternal transmission may suggest mitochondrial DNA related disease.
  • Dysmorphic features suggest a lysosomal storage disease (coarse facies, dysostosis, corneal clouding) peroxisomal biogenesis disorder or congenital disorders of glycosylation (CDG) (inverted nipples, fat pads).
  • Unusual diets or prolonged TPN with time off lipids and therefore vitamins may suggest a nutritional deficiency
  • See Examples of different diseases that cause cardiomyopathies

Pointers in history / examination:

  • A three generation family pedigree should be taken.
  • A family history with specific enquiry about; cardiac as well as renal disease, sensorineural hearing loss,
  • Recurrent miscarriages or early onset diabetes may suggest a metabolic disease. Mode of inheritance is generally autosomal recessive however an X-linked pattern may suggest Barth syndrome, Fabry and Hunter disease and maternal transmission may suggest mitochondrial DNA related disease

Checklist for acute presentation of DCM, HCM, RCM or acute myocarditis

Please Note: suggested investigations should be used as guide only and should not supersede clinical judgement

  1. Laboratory investigations taken on admission
    See  Investigations for acute presentation of DCM, HCM, RCM or acute myocarditis. Ensure all tests identified by * asterisk are taken prior to child receiving transfusion or immunoglobulin. 
  2. History: detailed history of presenting complaint, past history, developmental history. 
  3. Full examination: looking for multisystem disease or dysmorphic features.
  4. Routine tests: minimum of CXR, ECG, Echocardiogram 
    Consider Holter monitor and ophthalmology review
  5. Family screening 
    Detailed history (at least 3 generation pedigree should be drawn); history of sudden unexplained death in young people / Family history of cardiomyopathy / multisystem disease.
    Investigations; at least ECG and echocardiogram of parents and siblings 
    Further family screening may be indicated in first degree relatives and metabolic and genetic testing may be warranted. See referrals below. 
  6. Referrals
    If first tier investigations do not reveal cause, seek advice from cardiology, metabolic and genetic services and CIDG ( via operator) . 
    When requesting specific laboratory tests ensure you indicate your name and contact details clearly on the request form and the name of the consultant involved. 
    Refer case to CIDG unless a positive diagnosis of a non familial cause has been made e.g myocarditis. Please also inform CIDG when testing has identified a non familial cause 
    Contact cidgadmin@adhb.govt.nz. or phone 23634 and ask for the coordinator. NB CIDG will NOT chase up all the results, but will obtain consent from the family for DNA storage and testing and record family details 
  7. Consider biopsy - skin, skeletal, liver and myocardial 
    Ensure metabolic team involved prior to any samples being taken as they need to be stored in particular way;
    Skin biopsy is a 3-4mm punch biopsy (26A have these stored). Tissue is put into tissue transport media preferably (obtained from cytogenetics) or in sterile saline if happens overnight.
    Put on the form 'skin biopsy for fibroblast culture to cytogenetics' to ensure proper handling of the sample. Ensure the consultants name and contact details are included on the form. 
    Cardiac biopsy indicated: ensure metabolic team involved. PCR for candidate viruses (listed on Table 1).
  8. If infant / child deteriorating or for palliative care /dies
    Discuss with relevant consultants the appropriate tests and storage / handling of samples as soon as practicable
    Discuss with the Metabolic Consultant to ensure appropriate tests are arranged (see above for correct storage and labelling).
    Genetic testing: 1-2 ml minimum of EDTA blood - send to the molecular genetics lab for DNA extraction and storage.
    Take a skin biopsy for fibroblast culture in all patients within 12 hours of death
    Consider a muscle and/or liver biopsy, preferably pre or if not immediately after death, if mitochondrial or glycogen storage disease has been considered
    Discuss autopsy with family

Investigations for acute presentation of DCM, HCM, RCM or acute myocarditis

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Investigations acute presentation

Examples of different diseases that cause cardiomyopathies

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Different diseases

References

  1. Elliot, P., Andersson, B., Arbustini, E., Bilinska, Z., Cecchi, F.,Charron, P., Dubourg, O., Kuhl,U., Maisch. B., McKenna, W., Monserrat, L., Pankuweit, S., Rapezzi, C., Seferovic, P., Tavazzi, L and Keren , A. Classification of the cardiomyopathies: a position statement from the European society of cardiology working group on myocardial and pericardial diseases. European Heart Journal (2008) 29, 270-276. 
  2. Maron, B., Chair; Towbin, J, Gaetano Thiene, G., Antzelevitch, G., Corrado, D., Arnett, D., Moss, A., Seidman, C., Young, J. Contemporary Definitions and Classification of the Cardiomyopathies : An American Heart Association Scientific Statement From the Council on Clinical Cardiology, Heart Failure and Transplantation Committee; Quality of Care and Outcomes Research and Functional Genomics and Translational Biology Interdisciplinary Working Groups; and Council on Epidemiology and Prevention. Circulation (2006), 113:1807-1816.
  3. Colan, S. Classification of Cardiomyopathies. Progress in Pediatric cardiology , 23 (2007) 5-15
  4. Richardson, McKenna, W., Bristow, M., Maisch, B., Mautner, B., O'Connell, J., Olsen, E., Thiene, G., Goodwin, J., Gyarfas, IMartin, I., Nordet, P. Report of the 1995 World Health Organization/International Society and Federation of Cardiology Task Force on the Definition and Classification of cardiomyopathies. Circulation (1996) , 93(5):841-2]
  5. Gaetano Thiene, G., Corrado, D., Basso, C. Revisiting definition and classification of cardiomyopathies in the era of molecular medicine. European Heart Journal (2008) 29, 144-146
  6. Gajarski R and Towbin J. Recent advances in the etiology, diagnosis and treatment of myocarditis and cardiomyopathies in children. Current Opinion in Pediatrics. 1995; 7:587-594
  7. Mason JW. Classification of cardiomyopathies. In: Fuster V, Alexander RW, O'Rourke RA, eds. Hurst's the Heart, Arteries and Veins. 10th ed. New York, NY: McGraw Hill; 2001: 1941-1946.
  8. Park, M. The Pediatric cardiology hand book 3rd ed. Mosby , Inc., Philadelphia, U.S.A; 2003. 
  9. http://pcpgm.partners.org/lmm/tests/cardiomyopathy

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Document Control

  • Date last published: 01 August 2013
  • Document type: Clinical Guideline
  • Services responsible: Metabolic, Paediatric Cardiology
  • Author(s): Emma Glamuzina, John Stirling, Marion Hamer
  • Editor: Greg Williams
  • Review frequency: 2 years

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