Myocardial Disorders Flashcards

1
Q

2 classes of primary myocardial disease

A
  1. cardiomyopathy (dilated, hypertrophic, restrictive)

2. myocarditis

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2
Q

Primary problem in dilated cardiomyopathy?

A

systolic failure –> volume overload to increase preload –> all 4 chambers are eccentrically hypertrophied and contraction is worse

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3
Q

Primary problem in hypertrophic cardiomyopathy?

A

hypertrophy resulting in hypercontractility during systole but poor diastolic LV compliance due to normal ventricular cavity w/tons of concentric hypertrophy and consequent atrial dilation

*normal LVEF

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4
Q

Primary problem in restrictive cardiomyopathy?

A

poor diastolic compliance due to infiltration of cells (phages/myocytes)/amyloid/collagenthat makes ventricle stiff and consequently lead to atrial dilation

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5
Q

What’s the difference between a primary and secondary cardiomyopathy?

A

primary is predominantly myocardial vs. secondary is associated w/systemic/multiorgan disease (e.g. amyloidosis, hemochromatosis)

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6
Q

What kinds of proteins are often implicated in primary genetic cardiomyopathies?

A
  1. cytoskeletal
  2. sarcomeric
  3. ion channels
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7
Q

T/F an individual w/hypertrophic cardiomyopathy may develop DCM late in disease

A

T

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8
Q

What is the pathogenesis associated with arrhythmogenic RV cardiomyopathy?

A

defect in desmosomal proteins –> breakdown of myocyte connections (adhesion and communication/gap jxn) in RV –> fat replacement –> RHF + vtach/vfib

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9
Q

What protein is typically responsible in arrhythmogenic RV cardiomyopathy?

A

plakoglobin

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10
Q

Features of DCM?

A
  1. progressive dilation of all four chambers + hypertrophy + increased heart weight
  2. flabby walls
  3. endocardial thrombi
  4. hypertrophied myocytes + stretched thin myocytes + interstitial fibrosis
  • reduced LVEF
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11
Q

What are common causes of secondary DCM?

A

toxins like ethanol, adriamycin, prior myocarditis, pregnancy, hemochromatosis

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12
Q

Pathogenesis of DCM in hemochromatosis

A

excess iron absorption –> cardiac deposition –> interference w/ metal dependent enzymes for ox phos

    • diabetes and cirrhosis
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13
Q

Complications of DCM

A
  1. heart failure
  2. mitral insufficiency
  3. dysrhythmia
  4. emboli
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14
Q

Hallmark of Takotsubo cardiomyopathy

A

catecholamine excess –> reversible systolic dysfunciton with apical ballooning –> ECG looks like an MI

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15
Q

Features of HCM?

A
  1. stiff LV w/ impaired filling
  2. hypercontractile LV
    a. w/ LV outflow obstruction in 1/3 of cases–> IHSS/HOCM
    b. w/ interventricular septum effects in 90% of cases–> ASH (no dilation but asymmetric hypertrophy)
  3. myocyte hypertrophy and disarray w/ branching
  4. thickened intramyocardial arteries leading to angina, dysrhythmias
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16
Q

What is the marker of LVOT obstruction in someone with HCM?

A

septal scar from repeated battering from the anterior leaflet of MV –> bacterial endocarditis

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17
Q

Complications of HCM

A
  1. mitral valve endocarditis

2. emboli

18
Q

What is the difference in genetics between DCM and HCM?

A

HCM is 100% genetic vs 20-50% in DCM

19
Q

How does LVOT occur in HOCM?

A

septal hypertrophy/ASH –> LVOT
+ elongated mitral leaflets –> in systole, can get SAM (systolic anterior motion of mitral valve) due to drag in outflow tract –> mitral regurg due to malcoaptation of of MV + dynamic LVOT

result is initial LVOT + mitral regurg + a dynamic LVOT

20
Q

Mechanical txs for HOCM

A
  1. myomectomy (remove some basal septum)

2. ETOH septal ablation to shrink basal septum aka cause an MI

21
Q

Clinical manifestations of HOCM

A

dyspnea, angina, fatigue, syncope

22
Q

Physical exam in HOCM

A
  1. S4 due to diastolic dysfunction
  2. bifid pulse due to midsystolic obstruction
  3. murmur of outflow obstruction (crescendo/decrescendo) –> worsens with reduced preload
  4. mitral regurg
23
Q

What does the movement do to a murmur of HOCM vs AS? valsalva

A

reduce preload/afterload –> increase HOCM, reduce in AS

24
Q

What does the movement do to a murmur of HOCM vs AS? squatting

A

increase preload/afterload –> reduce murmur in HOCM, increase in AS

25
What does the movement do to a murmur of HOCM vs AS? standing
reduce preload/afterload --> increase HOCM, reduce in AS
26
What is a major risk of HCM?
sudden cardiac death --> VT/VF --> implantable defibrillators (AICD)
27
What is a known cause of collagen deposition leading to restrictive cardiomyopathy?
radiation
28
3 types of amyloid relevant to the heart
1. ig light chain derived associated w/ multiple myeloma (b cell proliferations) 2. soluble amyloid associated protein w/ rheumatoid arthritis 3. transthyretein w/senile cardiac amyloid
29
amyloid in old people
transthyretin
30
amyloid in RA
SAA-soluble amyloid associated protein
31
amyloid in multiple myeloma
Ig light chain
32
Features of restrictive cardiomyopathy
1. stiff ventricles + large atria 2. impaired filling --> decreased CO --> weakness/fatigue 3. normal ejection fraction in beginning 4. elevated venous pressures/congestion --> JVD, hepatomegaly, ascities, edema
33
Tx of restrictive cardiomyopathy
1. tx of underlying cause 2. diuretics (but have to be careful b/c can reduce CO) 3. digoxin (not in amyloidosis) 4. rhythm drugs 5. pacemaker 6. anticoagulation
34
What is myocarditis?
inflammation in myocardium which initiates myocyte damage --> immune, infections, unknown
35
Immunologic causes of myocarditis?
1. acute rheumatic fever 2. drug hypersensitivity (eosinophils) 3. post-viral (lymphocytic) 4. SLE and connective tissue diseases 5. transplant rejection
36
Which infections can lead to myocarditis?
Coxsackie, Chagas, lyme disease
37
MOA of viral myocarditis
t lymphocytes attack virally infected cells --> cross reacting antibodies
38
What does a myocarditis heart look like?
dilated, flabby heart like DCM w/normal heart weight
39
Clinical presentation of myocarditis
flu like illness +/- palpitation +/- chest pain to progressive/fulminant/lethal heart failure
40
In what cases do we get granulomas w/myocarditis?
sarcoidosis: granulomas are microscopic w/o necrosis (systemic) giant cell myocarditis: granulomas are macroscopic and necrotizing (only in heart)