cardiomyopathy Flashcards
Aetiological Classification of Cardiomyopathy
1 - Primary/ Intrinsic myocardial abnormality
Genetic
Idiopathic
Secondary to - systemic diseases, myocarditis
- Secondary/ Indirect myocardial dysfunction ( not CM, but acquire the functional patterns)
Valvular heart disease
Ischaemic heart disease
Hypertensive heart disease
what happens in Dilated Cardiomyopathy
Most common cardiomyopathy Probably not a distinct entity Impaired systolic LV contraction LV hypertrophy and increase in heart weight Associated with dilatation aka congestive cardiomyopathy
Dilatation often masks hypertrophy
cellular processes occuring in cardiomyopathy
Nuclear hypertrophy and increased myocyte width
Interstitial fibrosis and T-lymphocyte infiltration
causes of dilated cardiomyopathy
1 - Non genetic Alcohol Anthracycline chemotherapeutic agents Previous myocarditis Nutritional deficiency Peripartum
- Genetic:
30-40% of cases
Several genes, including dystrophin
Part of Duchenne & Becker muscular dystrophy
3.Idiopathic
effects and treatment of dilated cardiomyopathy
Usually slowly progressive heart failure Also mural thrombus with embolism Sudden death from arrhythmia rare Prognosis dependent on severity 50% patients dead within 2 years
Treatment
Medical
Cardiac transplantation
what is Hypertrophic Cardiomyopathy
Distinct genetic disorder ( in nearly 100% cases)
Usually asymmetrical LV hypertrophy
Increased heart weight and LV hypercontraction
Impaired diastolic filling
Often outflow obstruction
aka (Familial) Hypertrophic (Obstructive) CM
Often asymmetrical left ventricular hypertrophy
Much less commonly symmetrical hypertrophy
Sub-aortic fibrosis due to impact of anterior mitral valve leaflet
cellular level of hypertrophic cardiomyopathy
Myocyte disarray: Nuclear pleomorphism and disorganised myocyte architecture
Myocyte disarray: Interstitial fibrosis & whorling of myocytes around a central focus of collagen
Genetic Basis of HOCM
50% familial autosomal dominant
50% sporadic new mutations
Defect in 1 of 4 genes encoding cardiac contactile proteins:
Beta-myosin heavy chain Troponin T Troponin I Alpha-tropomyosin Myosin binding protein C Essential and regulatory myosin light chains
effects of having HOCM
Sudden cardiac death via arrhythmia Syncopal attacks on exercise Atrial fibrillation +/- thromboembolism Mitral valve endocarditis Progressive heart failure rare Prognosis depends on mutation & severity Compatible with normal life-span Commonest cause of sudden cardiac death in young
treatment of HOCM
Medical
Dual chamber cardiac pacing
Surgical septal myomectomy
Ablative septal therapy (alcohol)
what happens in Restrictive cardiomyopathy
Decrease in ventricular compliance Impaired ventricular filling during diastole Systolic function less affected LV wall has normal proportions Heart weight may be normal or increased
Some also include the obliterative CM’s in this category
causes of restrictive cardiomyopathy
Idiopathic Amyloidosis Radiation Sarcoidosis Metastatic tumour Deposition via inborn error of metabolism/ storage disorders Genetic
what is amyloidosis and how does it affect the heart to cause restrictive cardiomyopathy
Any extra-cellular protein with a Beta-pleated sheet crystalline structure
Many types, 4 of which commonly affect heart:
Systemic AA derived from serum amyloid A: Chronic inflammation or Familial
Systemic AL derived from light chains:Plasma cell neoplasms
Systemic ATTR derived from transthyretin:Familial genetic disorder or old age
AANF derived from atrial natriuretic factor: Isolated senile atrial amyloidosis
Systemic amyloid deposition produces bilateral hypertrophy
effect of having restrictive cardiomyopahty and treatment
Pulmonary hypertension
Right ventricular hypertrophy and failure
Treatment
Medical
Prevention of progression
Cardiac transplantation
what is myocarditis
Primary inflammation of myocardium Usually concomitant febrile illness Variable symptoms depending on severity Heart chambers dilated or normal Normal heart weight Often systolic dysfunction +/- mitral regurgitation May be associated with pericarditis
infective causes of myocarditis
Cardioselective viruses:
Coxsackie A&B, Adenovirus, ECHO viruses
Most common cause of significant myocarditis
May be associated with skeletal myositis
Non-selective viruses :
Any systemic viral infection
Common in HIV, Rubella, Mumps, CMV, Polio
Usually asymptomatic
Dense infiltrate of T-lymphocytes with necrosis seen when due to viral infection
Non-viral causes: Chlamydia Rickettsiae (typhus fever) Bacteria (diptheria, meningococcus, Lyme) Fungi (candida, aspergillus) Protozoa (Trypanosoma, toxoplasmosis) Helminths
non infective causes of myocarditis
Immune reactions: Post-viral Rheumatic fever SLE Drug hypersensitivity Transplant rejection
Unknown aetiology:
Sarcoidosis
Giant cell myocarditis
effects of myocarditis and treatment
Acute heart failure
Sudden cardiac death via arrhythmia
Treatment
Supportive therapy
Appropriate antimicrobials
types of hypertension
Benign (chronic) hypertension:
Asymptomatic
Insidious, slowly progressive organ damage
Malignant (Accelerated-phase) hypertension:
Rapid rise leading to symptomatic organ damage
De-novo or following benign hypertension
De-novo common in young Afro-Caribbean males
complications of hypertension
Vessels:
Atherosclerosis
Aortic dissection
Aneurysm rupture
Heart:
LVH
LVF
Brain: Cerebral haemorrhage (stroke)
Kidney:
Benign nephrosclerosis
Malignant nephrosclerosis
what happens in aortic dissection
Intimal tear allows blood to enter media
Tracks along laminar plane of media
Causes blood-filled ‘false’ channel
Usually thoracic - may involve aortic valve root
aka dissecting aneurysm but less appropriate term
Type A if involves ascending aorta
Type B if distal to aortic arch
what happens in hypertensive nephrosclerosis
Benign nephrosclerosis :
- Proteinuria
- Progressive chronic renal failure
- Kidneys reduced in size and weight
- Diffusely granular surface
from small foci of scarring in
benign nephrosclerosis - Glomerulosclerosis and tubular atrophy
Malignant nephrosclerosis:
- Acute renal failure
- Kidney size and weight normal if de-novo
- Permanent renal failure if not treated quickly
- ‘Flea-bitten’ kidneys in malignant nephrosclerosis: Small haemorrhages due to rupture of arterioles and glomerular capillaries
- Hyperplastic arteritis:‘Onion-skinning’ appearance due to
intimal fibroblastic proliferation - Necrotising arteriolitis: Fibrinoid necrosis of arteriolar wall
what happens in hypertensive heart disease
Left ventricular hypertrophy Concentric distribution (symmetrical) Compensatory adaptation Often asymptomatic Eventual decompensation and dilatation
Left ventricular failure:
pulmonary oedema
systemic hypoxia
Also risk of sudden cardiac death via arrhythmia
