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19 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Defn |
Dxs of myocardial dysfxn in which the myocardial is structurally and/or fxnally abn. in the absence of definite dx able to cause the myocardial pathology. |
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Classification and mechanism of heart failure |
Hypertrophic - impairment of compliance (diastolic dysfxn) Arrhythmogenic/RV dysplasia - Restrictive - impairment of compliance (diastolic dysfxn) Dilated - impairment of contractility (systolic dysfxn) |
HARD |
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Which is the most cmn |
DCM |
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DCM is xzed by |
Progressive cardiac dilation and contractile (systolic) dysfxn. Presence of a dilated and poorly fxning left or both ventricles.
Diagn may be in assoc with CVdx, but extent of myocardial dysfxn cannot be explained exclusively by loading cdns.. valvular or htn dx... or IHD. |
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Causes of DCM |
Dietary – beri-beri (thiamine deficiency)
Hereditary – familial DCM, muscular dystrophies (Duchenne, myotonia, mitochondrial)
Endocrine – hypothyroidism, thyrotoxicosis, phaeochromocytoma
Infective – viruses (coxsackie), Chagas’ disease
Toxins – alcohol, drugs (anthracyclines)
Infiltrative – sarcoid, iron overload (haemochromatosis, excess blood transfusions) |
Dilated Hearts End In Terrible Infiltration |
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Pathogenesis DCM |
Genetic causes: autosomal dominant inheritance with incomplete and age dependent penetrance. Linked to a diverse group of over 40 genes. Mutations in encoding cytoskeleton gene or proteins that link the sarcomere to the cytoskeleton. (E.g. alpha cardiac actin.) X-Linked assoc with dystrophin gene mutations Mitochondrial gene mutation (rare) - genes that encode proteins involved in OP and fatty acid oxidation therefore leading to defective ATP generation. In fam hx, special attention to hx of muscular dystrophy, mitochondrial dx (E.g. fam DM, deafness, epilepsy) and s&s of inherited metabolic dx.
Infection: nucleic acid footprints of cocksackie virus B & other enteroviruses detected in myocardium. Infectious myocardial may progress to DCM
alcohol and toxins: alcohol and it's metabolites(and other toxins ie doxorubicin and cobalt)... acetaldehyde... have a direct toxic effect on myocardium. Chronic alcoholism assoc with thiamine def, beriberi.
Peripartum CM: occurs late in gestation or several wks to months postpartum. Contributing factors: pg htn, vol overload, nutrion def, met derangements e.g. DM, immunologic responses. Prolactin cleavage 2° to unbalanced peri/postpartum oxidative stress. Cleaved into a potent antiangiogenic, proapoptotic, proinflmtory 16kDa fragment. ~ half recover spontaneously
Iron overload: from hereditary hemochromatosis or multiple transfusions. Interference with metal dependent enzyme systems or production of reactive O2 spp.
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Morphology |
Gross Enlarged heart that's 2-3× normal weight Ventricular chamber dilation with thickened or normal thickness walls Dilation of vascular orifices as 2° change due to dilation of chambers Mural thrombi may be found 2ithin ventricles & atrial appendages. Micro Interstitial and perivascular fibrosis of varying degree Myocytes exhibit hypertrophy with enlarged nuclei, some are attenuated, stretched and irregular Myocardial necrosis at subendocardium. In iron overload... accum of intramyocardial hemosiderin demo by Prussian blue |
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Clin features |
Slow or rapid progression CHF sympt: dyspnoea, easy fatig, poor exertions capacity Cachexia and peripheral edema late in dx Thromboembolic complications Sudden death due to ventricular fibrillation |
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Mx |
Cardiac transplant - definitive Implantation of long term ventricular assist. |
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Stress induced/ Takutsubo |
Hx of intense emotional or physical stress & typical LV contractile dysfxn Transient and reversible CF indistinguishable from acute myocardial synd, coronary angiography to rule out CAD shape of LV resembles Takutsubo, narrow neck, wide base Elevated lvls of circulating catecholamines Resolution dys to wks after initial ppt confirms diagn. |
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Arrhythmogenic/RV dysplasia xd by |
RV myocyte replacement by massive fatty infiltration and (lesser) fibrosis. Manifestation of ventricular tachycardia and fibrillation |
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Pattern of inheritance |
Autosomal dominant with variable penetrance Mutation of genes encoding desmosal jxn proteins as well as proteins that interact with desmosome |
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Manifestations |
Rhythmic disturbances that cause sudden cardiac death. Palpitations Syncope Rt/biventricular HF - less cmn, in pts protected from SCD by ICDevices |
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Hypertrophic CM xd by |
Myocardial hypertrophy, defective diastolic filling and in 1/3 ventricular outflow obstruction |
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Pathogenesis |
Heterogeneous autosomal dominant with variable penetrance caused by atleast 10 genes encoding for sarcomeric proteins. Beta myosin heavy chain is most freq affected. Mutations ^ myofilament activation which results in myocyte hypercontractility with ^ in energy use . (Same genes mutated in DCM but in DCM, the my decrease motor fxn.) |
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Morphology |
Gross Massive myocardial hypertrophy without ventricular dilation Asymmetrical interventricular septum thickening (septal hypertrophy) Mostly affect LV, RV 17% (middle and apical protion) Histo Myocyte hypertrophy Disarray with bizarre enlarged nuclei Interstitial fibrosis |
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CF |
Exertional dyspnoea Harsh systolic ejection murmur MI with angina Atrial and ventricular fibrillation Mural thrombus 4mn Infective end of mitral valve CHF Sudden death (in 1/3 of young athletes, HCM is the underlying cause) |
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Mx |
Therapy that promotes ventricular realaxation: Partial surgical excision Controlled alcohol induced infarction of septal ms cn relieve outflow tract obstructn |
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Restrictive CM is xd by |
1° decrease in ventricular compliance, resulting in impaired ventricular filling... reduced diastolic vol (wall is stiffer) Systolic fxn is normal or near normal. |
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