Myocardial Disorders

Question 1

2 classes of primary myocardial disease

Answer 1

1. cardiomyopathy (dilated, hypertrophic, restrictive)

2. myocarditis

Question 2

Primary problem in dilated cardiomyopathy?

Answer 2

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

Question 3

Primary problem in hypertrophic cardiomyopathy?

Answer 3

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

Question 4

Primary problem in restrictive cardiomyopathy?

Answer 4

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

Question 5

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

Answer 5

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

Question 6

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

Answer 6

1. cytoskeletal
2. sarcomeric
3. ion channels

Question 7

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

Answer 7

T

Question 8

What is the pathogenesis associated with arrhythmogenic RV cardiomyopathy?

Answer 8

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

Question 9

What protein is typically responsible in arrhythmogenic RV cardiomyopathy?

Answer 9

plakoglobin

Question 10

Features of DCM?

Answer 10

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

Question 11

What are common causes of secondary DCM?

Answer 11

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

Question 12

Pathogenesis of DCM in hemochromatosis

Answer 12

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

• • diabetes and cirrhosis

Question 13

Complications of DCM

Answer 13

1. heart failure
2. mitral insufficiency
3. dysrhythmia
4. emboli

Question 14

Hallmark of Takotsubo cardiomyopathy

Answer 14

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

Question 15

Features of HCM?

Answer 15

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

Question 16

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

Answer 16

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

Question 17

Complications of HCM

Answer 17

1. mitral valve endocarditis

2. emboli

Question 18

What is the difference in genetics between DCM and HCM?

Answer 18

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

Question 19

How does LVOT occur in HOCM?

Answer 19

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

Question 20

Mechanical txs for HOCM

Answer 20

1. myomectomy (remove some basal septum)

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

Question 21

Clinical manifestations of HOCM

Answer 21

dyspnea, angina, fatigue, syncope

Question 22

Physical exam in HOCM

Answer 22

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

Question 23

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

Answer 23

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

Question 24

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

Answer 24

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

Question 25

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

Answer 25

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

Question 26

What is a major risk of HCM?

Answer 26

sudden cardiac death --> VT/VF --> implantable defibrillators (AICD)

Question 27

What is a known cause of collagen deposition leading to restrictive cardiomyopathy?

Answer 27

radiation

Question 28

3 types of amyloid relevant to the heart

Answer 28

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

Question 29

amyloid in old people

Answer 29

transthyretin

Question 30

amyloid in RA

Answer 30

SAA-soluble amyloid associated protein

Question 31

amyloid in multiple myeloma

Answer 31

Ig light chain

Question 32

Features of restrictive cardiomyopathy

Answer 32

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

Question 33

Tx of restrictive cardiomyopathy

Answer 33

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

Question 34

What is myocarditis?

Answer 34

inflammation in myocardium which initiates myocyte damage --> immune, infections, unknown

Question 35

Immunologic causes of myocarditis?

Answer 35

1. acute rheumatic fever 2. drug hypersensitivity (eosinophils) 3. post-viral (lymphocytic) 4. SLE and connective tissue diseases 5. transplant rejection

Question 36

Which infections can lead to myocarditis?

Answer 36

Coxsackie, Chagas, lyme disease

Question 37

MOA of viral myocarditis

Answer 37

t lymphocytes attack virally infected cells --> cross reacting antibodies

Question 38

What does a myocarditis heart look like?

Answer 38

dilated, flabby heart like DCM w/normal heart weight

Question 39

Clinical presentation of myocarditis

Answer 39

flu like illness +/- palpitation +/- chest pain to progressive/fulminant/lethal heart failure

Question 40

In what cases do we get granulomas w/myocarditis?

Answer 40

sarcoidosis: granulomas are microscopic w/o necrosis (systemic) giant cell myocarditis: granulomas are macroscopic and necrotizing (only in heart)