Cardiomyopathies

Front 1

types cardiomyopathies and typical dysfunction

Back 1

1) Dilated: impaired systolic contraction

2) Hypertrophic: impaired diastolic relaxation (usually intact systolic)

3) restrictive: abnormally stiff, impaired diastolic relaxation

LA enlargement is common to all three types

Front 2

definition cardiomyopathy

Back 2

group of heart disorders in which major structural abnormality is limited to the myocardium
- often result in symptoms of heart failure
LA enlargement is common to all types

excludes heart impairment from other defined CV diseases

many times etiology remains unknown

Front 3

Etiology of DCM

Back 3

1) Idiopathic
2) Familial/genetic
3) Inflammatory:
- progression of viral myocarditis (immune-mediated injury?)
= coxsackievirus group B
= parvovirus B19
= adenovirus etc
Non infectious:
- peripartum CM - HF symptoms in last month of pregnancy - 6m postpartum
- CT disease
- Sarcoidosis
4) Toxic
- alcoholic CM - potentially reversible if identified!
- chemotherapeutic agents
5) Metabolic
- Hyperthyroidism
- Chronic hypoCa+ or hypophosphatemia
6) Neuromuscular

Front 4

increased risk of thromboembolic complication in DCM because:

Back 4

1) stasis in ventricles from poor systolic funciton

2) stasis in atria due to chamber enlargement or a Fib

3) venous stasis from poor circulatory flow

definite anticoags if:
A fib
previous TE
intercardiac thrombus visualized w Echo

LV EF <30% probably anticoag

Front 5

Treatment considerations in DCM

Back 5

1) tx HF: diuretics, vasodilator (ACE inhib, ARB); beta-blocker

2) prevent and tx arrythmias
- maintain electrolyte balance
- amiodrone
- ICD*
- cardiac resynchronization therapy

3) Prevent thromboebolic events
- anticoagulants

4) Cardiac transplant - better 5 yr prognosis than other tx

Front 6

definition HCM

Back 6

usually asymmetric LV hypertrophy (90% cases septum) NOT caused by chronic pressure overload (ie systemic HTN or aortic stenosis)

thick muscle = stiff = impaired relaxation/filling and high diastolic pressures; also arrythmias

may have transient obstruction of LV outflow during systole

hypertrophy = chaotic, disarray

Front 7

HCM etiology

Back 7

familial
autosomal dominant
variable penetrance
100s of mutations
- all part of sarcomere complex = impaired contractile fn = compensatory hypertrophy and proliferation of fibroblasts

Front 8

cause of outflow obstruction in HCM

Back 8

1) rapid blood flow toward aortic valve from narrowed outflow tract

2) rapid flow creates Venturi forces that draw anterior mitral valve leaflet toward septum

3) valve leaflet abuts hypertrophied septum = transient obstruction of blood flow into aorta

negative inotropic drugs and conditions that enlarge LV increase distance bw valve leaflet and septum = reduced obstruction; vice versa for conditions that decrease LV size, and positive inotropic drugs

Front 9

Clinical findings HCM

Back 9

- presentation mid 20s
- dyspnea (^ diastolic P > ^ pulm cap P)
- angina (high O2 demand, narrowed smaller branches of coronary arteries in walls)
- syncope (arrhythmias; a fib not well tolerated; v fib may cause sudden cardiac death)
- S4, double apical impulse

Front 10

orthostatic lightheadedness in pts with HCM and outflow tract obstruction

Back 10

- venous return to heart decreases on standing from pooling of blood in lower extremities
= decrease size LV
= intensified outflow tract obstruction
= reduced CO and cerebral perfusion

Front 11

Risk factors for sudden death in HCM

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- history of syncope
- fam hx sudden death
- some high risk HCM mutations
- extreme hypertrophy (>30mm in thickness)

incidence: 2-4% adults, 4-6% kids/adolescents

Front 12

HCM on EKG

Back 12

- LVH, LA enlargement
- Prominent Q waves in inf and lat leads from amplified initial depol in enlarged septum
- sometimes diffuse T wave inversions
- A and V arrhythmias

Front 13

HCM treatment

Back 13

1) Beta blockers
= reduced MO2 demand (decrease angina and dyspnea)
= ^ passive diastolic filling time (bc dec HR)
= decrease hz ventricular ectopic beats
2) Ca Channel antagonists: reduce V stiffness
3) careful use diuretics to decrease pulm congestion w/o volume depletion
4) antiarrhythmics to avoid a fib (amidrone)
5) avoid strenuous exercise
6) ICD if high risk v fib
7) myomectomy for those who dont respond to pharma - excision hypertrophied septum; percutaneous septal ablation

Front 14

definition RCM

Back 14

characterized by abnormally rigid, but not necessarily thickened, ventricles
= impaired diastolic filling
- normal/near norm systole

results from:
1) fibrosis/scarring of endomyocardium
2) infiltration of myocardium by abnormal substance

Front 15

amyloidosis

Back 15

most common recognized cause of RCM in nontropical countries

insoluble misfolded amyloid fibrils deposit in tissues
1* - tumor secretion - see most clinical cardiac issues
2* - chronic inflam conditions
hereditary - point mutations
senile

Front 16

consequences of RCM

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1) elevated systemic and pulmonary venous pressures, signs of R and L vascular congestion

2) reduced ventricular cavity size w decreased SV and CO

Front 17

differentiation of RCM from constrictive pericarditis

Back 17

diagnostic:
-transvenous endomyocardial biopsy (presence of infiltrates)
- CT
- MRI
(both see thickened pericardium)

Front 18

treatment RCM

Back 18

- treat underlying cause!
- symptomatic tx
= salt restriction, cautious use diuretics to improve congestion
= maintenance sinus rhythm
= oral anticoags

Front 19

etiologies of RCM

Back 19

Noninfiltrative
- idiopathic
- scleroderma
Infiltrative:
- Amyloidosis
- Sarcoidosis
Storage diseases:
- Hemochromatosis
- Glycogen storage diseases
Endomyocardial disease:
- endomyocardial fibrosis
- metastatic tumors
- radiation therapy