Myocardial pathology Flashcards
layers of heart
Deep to outer
1) endothelium
2) myocardium
3) visceral pericardium
anterior layer of heart
LAD artery visible in pericardium
characteristics of normal cardiac muscle
1) rich vascularity
2) minimal supporting connective tissue
3) cytoplasmic branches
4) distinct sarcomeric pattern
Parts of sarcomere
1) light chain - attach to z disk
2) heavy chain - btwn light chains
Z-disk proteins
1) alpha actinin
2) myotillin
3) filamin C
4) ZASP
5) telethonin
Parts of heavy chain in sarcomere
1) myosin
2 isoforms = fast and slow twitch
parts of light chain in sarcomere
1) actin
2) troponin T = Troponin-linking
3) troponin I = inhib ATPase
4) troponin C = Ca2+ binding
5) nebulin
6) tropomyosin 2,3
define cardiac myxoma
1) benign neoplasm
MOST COMMON PRIMARY TUMOR OF HEART IN TEEN + ADULT
2) frequency= rare
3) location = MAINLY LA
patient population with cardiac myxoma
teen
adult
structure of cardiac myxoma
1) pedunculated or sessile mass
2) ball-valve obstruction and damage
most common valve involved in cardiac myxoma
mitral valve
dangers of cardiac myxoma
frags can embolize into systemic circulation and lodge in brain/kidney
–> syncope/sudden death
Other primary neoplasms in heart
1) lipoma (benign)
2) rhabdomyoma (benign)
3) angiosarcoma (malignant
define rhabdomyoma
benign neoplasm
made of skeletal muscle cells
MOST COMMON PRIMARY CARDIAC TUMOR OF INFANCY/CHILDHOOD
define angiosarcoma
malignant
tumor of blood vessels
define thrombus
blood clot
mass in heart
possible cardiac metastases of breast cancer
metastasis of leukemias and lymphomas
1) inside of heart (conduction prblems)
2) pericardium (restrictive pericarditis)
causes of infectious myocarditis
1) viral
2) bacterial
3) fungal
4) parasitic
define viral myocarditis
inflammation (lymphocytes) injury to myocardium
common viral causes of viral myocarditis
coxsackie A or B
enteroviruses
types of parasitic myocarditis
tricinosis (trichinella)
chagas disease (trypanosoma cruzi)
define trichinosis
caused by raw pork, game animal
most common in skeletal muscle
define chagas disease
trypanosoma cruzi (biting fly)
over time, immune system attacks
fungal myocarditis
most common in which type of patients
mostly immunocompromised
such as with chemo and steroids
define autoimmune diseases (collagen vascular disease/connective tissue disease)
systemic autoimmune disease affect many organs
examples of systemic autoimmune disease
1) SLE
2) scleroderma
3) systemic sclerosis
4) rheumatoid arthritis
organ-specific autoimmune disease
lung and kidney
goodpasture
organ-specific autoimmune disease
RBC
autoimmune hemolytic anemia
organ-specific autoimmune disease
thyroid
graves disease
if heart involved, then usually systemic autoimmune
involves pericardium, myocardium, endocardium
–> heart blood vessel attack = vasculitis –> small infarcts
define vasculitis
heart blood vessel attack
define toxic effects on heart
vary amongst patients
some sensitive/some not
if patient not sensitive to toxic effect that means ____
idiosyncratic
medications for toxic metabolic diseases
adriamycin = chemo drug for cumulative dose-dependent toxicity
exogenous substances that can cause toxic disease
ethanol (or metabolite acetaldehyde)
cobalt from artificial joint prosthesies
define hemochromatosis
inherited excess iron in muscle
hemochromatosis on stain
lipofuscin pigment (wear and tear) does not stain with iron
define amyloidosis
protein deposit as “beta pleated sheats”
or immunoglobulin light chain
example of amyloidosis involving laying down beta pleated sheet proteins
multiple myeloma = plasma cell neoplasm/dyscrasia
example of amyloidosis involving immunoglobulin light chain (k, gamma)
amyloid P
trasthyretin/prealbumin
genetics of amyloidosis
MOST CASES SPORADIC
symptomatic effects of amyloidosis on organs
wax-like
heart kidney nerves liver spleen
amyloidosis on stain
cardiomyocytes separated by fibrosis + AMORPHOUS (AMYLOID) material
special stains for amyloidosis
1) congo red
2) congo red stain polarized
LOOK FOR AMYLOIDOSIS NOT SPECIFIC FOR PROTEIN
what does congo red stain visualize as?
salmon orange color of amyloid
what does congo red stain polarized visualize as
amyloid = “granny apple green”
birefringence
define= systemic metabolic disease
disease affect muscle (glycogen storage + muscular dystrophy)
include cardiac
define cardiomyopathy
primary abnormality in myocardium (myofiber)
EXCLUDE SECONDARY CAUSES
examples of secondary cardiomyopathy
EXCLUDED FROM CARDIOMYOPATHY
1) ischemia
2) hypertensive disease
3) valve assoc abnormality
clinical effects of cardiomyopathy
electrical and mech dysfunction
mechanism of dilated cardiomyopathy
impaired contractility (systolic dysfunction)
because heart is so thick –> can cause stasis of blood
mechanism of hypertrophic cardiomyopathy
impaired compliance and diastolic relax (diastolic dysfunction)
mechanism of restrictive cardiomyopathy
impaired complaince stiff LV with impaired diastolic relaxation (diastolic dysfunction) because so stiff
normal systolic fxn
Mechanism of myocyte hyperrophy causing cardiac dysfunction
1) HTN, valvular disease, MI
2) incr cardiac work
3) incr wall stress
4) cell stretch
5) hypertrophy/dilation
6) cardiac dysfunction
reason why HTN causes myocyte hypertrophy
pressure overload
reason why valvular disease causes myocyte hypertrophy
pressure +/- volume overload
reason why MI causes myocyte hypertrophy
regional dysfunction + volume overload
microscopic appearance of dilated cardiomyopathy
nonspecifc changes
complications of dilatedd cardiomyopathy
mural thrombus form
systemic emboli
dysarrhythmia
big/dilated heart (thick walls)
causes of DCM
1) genetic
2) infectious
3) alcoholic
4) peripartum
causes of HCM and murmur
100% genetic
systolic murmur loudest at left sternal border + mitral regurg
effect of hypertrophic cardiomyopathy on heart strxr
THICK IV SEPTUM bulge in LV outflow tract during early systole
outflow obstruction of aortic valve
anterior leaflet of mitral valve impinge on septal wall during systole
type of murmur in HCM
ejection murmur
complications of HCM
sudden death
pathologic change in HCM
hypertrophy + disarray of fibers
restrictive cardiomyopathy inheritance
ACQUIRED NOT GENTIC
causes of restrictive cardiomyoapthy
1) amyloid deposition
radiation induced fibrosis
scleroderma
hemochromatosis
