Cardiovascular Flashcards
What tool is used to diagnose cardiomyopathy?
Endomyocardial biopsy
What genetic mutation is linked to familial Dilated cardiomyopathy?
Titan mutations
In the sarcomere, stretches from one Z line to the next
The genetic cause of autosomal dominant dilated cardiomyopathy involves mutations in genes involving which cellular structure?
Cytoskeleton
(alters the contractile mechanism of the cell wall)
Which genetic mutation is most common in boys of teenage years with rapidly progressive cardiomyopathy?
Mutation in dystrophin gene
Boys with Duchenne and Beckers muscular dystrophy
Mutation of which genes can cause Dilated Cardiomyopathy?
- Titan (sarcomere)
- Cytoskeletal genes
- Mitochondrial genes
- beta oxidation of fatty acids
- oxidative phosphorylation
- Dystrophin
What are the causes of dilated cardiomyopathy?
- Genetic mutation
- Myocarditis (due to coxsackie B or other enteroviruses)
- Alcohol abuse
- beriberi is similar
- Drugs
- Doxorubicin
- Cocaine
- Pregnancy
- Iron overload
- Hemochromatosis
- multiple blood transfusions
- Cobalt exposure (ingestion?)
- Supraphysiologic stress
- tachycardia
- hyperthyroidism
What are common problems caused by DCM?
- Mural thrombus formation in atria and ventricles
- Functional mitral or tricuspid regurgitation due to ventricular dilation
What is the primary cardiac abnormality in DCM?
- Impairment of left ventricular function
- Systolic dysfunction occurs
- Ventricles cannot pump
- Ultimately causes biventricular CHF
What is the ejection fraction of end stage DCM?
<25%
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) can be caused by defects in genes involving what cell structure?
Desmosomes (cell-cell adhesions)
What are the signs/symptoms of Naxos Syndrome? What is the cause?
- Signs/Symptoms
- Arrhythmogenic cardiomyopathy
- plantar / palmar hyperkeratosis
- Cause:
- mutations in plakoglobin
What are the histological changes of ARVC?
- RV wall is very thinned
- causes failure and rhythm disturbances
- Loss ofmyocytes
- Fatty infiltration
- Interstitial fibrosis
Hypertrophic Cardiomyopathy (HCM) is caused by mutations affecting what cellular structure? What is the most common mutation?
- Mutations affecting sarcomeres
- beta-myosin heavy chain is most common mutation
- AD
- 100% genetic
How does HCM cause heart failure?
Decrease in chamber size and compliance => Decreased SV => HF
What phase of the cardiac cycle is affected by hypertrophic cardiomyopathy? Dilated CM? Restrictive CM?
- HCM: diastolic filling disorder, massive muscle mass prevents filling
- DCM: Systolic dysfunction, thinned ventricles cannot pump
- RCM: Diastolic, decreased compliance restricts ventricular filling
Where is hypertrophy usually located in HCM? What can result?
- thickening occurs most often in the IV septum
- Location is often subaortic
- Result:
- aortic outflow obstruction
- Contact of anterior mitral leaflets with septum (thickening)
What is the histologic characteristic specific to HCM? What happens to individual myocytes?
- Characteristic:
- Haphazard disarray of myocyte
- Individual myocytes
- Hypertrophy
What is the most common cause of unexplained death in young athletes?
HCM
What murmur is found in HCM? What is the cause of the murmur?
- Murmur:
- harsh, systolic ejection murmur
- Cause
- anterior mitral leaflet moving towards septum
What are the symptoms of HCM?
- Exertional dyspnea
- LV outflow obstruction leads to increased pulm venous pressure
- Angina
- focal ischemia from hypertrophy (can’t supply whole wall) and abnormal intramural arteries
What major clinical problems are associated with HCM?
- A fib w/ mural thrombus formation
- Cardiac failure
- Ventricular arrhythmias
- Sudden cardiac death
What drug is used to treat HCM?
beta blockers (help ventricular relaxation)
Which part of the cardiac cycle is affected by restrictive cardiomyopathy?
Diastole
(Cant fill due to decreased compliance)
What causes Restrictive cardiomyopathy?
- Fibrosis
- sarcoidosis
- Amyloidosis
- Hemachromatosis
- Leukemia or metastatic tumor
- Storage diseases