SM 146a - Myocardial Pathology Flashcards

1
Q

LV hypertrophy is present in hypertrophic cardiomyopathy, but also in highly-trained athletes.

Describe the differences in histology

A
  • Hypertrophic cardiomyopathy
    • Genetic cause
    • Myofibers go in all directions
    • Myocyte branching
    • Asymmetric septal hypertrophy
  • Highly-Trained athletes
    • Physiologic result of an adjustment to increased volume (due to increased venous return)
    • Myocytes are organized; usually in the same direction to maximize efficiency of contraction
    • Symmetric hypertrophy
    • Reversible
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2
Q

Describe the features of hypertrophic cardiomyopathy

A
  • Idiopathic hypertrophy
    • Not caused by increased hemodynamic load
  • Hypertrophy involves the septum more commonly than the free wall
    • Obstruction of outflow -> Subaortic stenosis
    • Resistance to ventricular filling
  • Small LV chamber
    • Not dilated
  • Wall thickening
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3
Q

What are the most common causes of dilated cardiomyopathy?

(aka congestive cardiomyopathy)

A
  • Alcohol (1/3 of all DCM)
  • Pregnancy (peripartum)
  • Genetic influence
  • Recent viral infection
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4
Q

What are the most common immune-mediated causes of pericarditis? (3)

A

Systemic Lupus Erythematous

Rheumatic Fever

Rheumatoid Arthritis

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5
Q

In general, how are tumors of the heart treated?

What is the major side effect of these drugs?

A

Immune checkpoint inhibitors

  • Nivolumab
  • Ipilimumab

These drugs increase the patient’s risk of myocarditis; they attack the tumor and the normal heart tissue

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6
Q

What are the most common viral causes of pericarditis? (2)

A

Coxsackie virus

ECHO (Enteric Cytopathic Human Orphan) Virus

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7
Q

What do all cardiomyopathies have in common?

A

Intrinsic myocardial dysfunction

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8
Q

What are the symptoms of hypertrophic cardiomyopathy?

A
  • Sudden cardiac death
  • Angina
  • Syncope
  • Systolic murmur
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9
Q

Describe the most common causes of restrictive cardiomyopathy

A
  • Loeffler’s endocarditis
    • Hypereosinophilia and fibrous thickening of the endocardium, usually with large thrombi against the ventricle walls (https://www.orpha.net/consor/cgi-bin/OC_Exp.php?Expert=75566&lng=EN)
  • Endomyocardial fibrosis
    • In Sub-Saharan Africa
  • Primary endocardial fibroelastosis
    • In children, usually due to ischemia/hypoxia in fetal development
  • Carcinoid syndrome
    • Due to tumor
  • Infiltrative process -> myocardial restrictive cardiomyopathy
    • Amyloidosis
    • Fibrosis
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10
Q

Which cardiomyopathy has provided a “model for the genetics of CV disease?”

A

Hypertrophic cardiomyopathy

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11
Q

What is Loeffler’s Endocarditis?

A

Hypereosinophilia and fibrous thickening of the endocardium, usually with large thrombi against the ventricle walls

(https://www.orpha.net/consor/cgi-bin/OC_Exp.php?Expert=75566&lng=EN)

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12
Q

What are the most common storage-disorder causes of secondary cardiomyopathy?

A
  • Glycogen storage
  • Hunter-hurler
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13
Q

What are the most common parasitic causes of myocarditis?

A

T. Cruzi -> Chagas disease

Toxoplasmosis

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14
Q

Describe the features of restrictive cardiomyopathy

A
  • Stiff left ventricle
    • -> Inhibition of diastolic ventricular filling
    • -> Left heart failure
  • Myocardial restrictive cardiomyopathy ->
    • Thickening
    • Inelasticity
    • Sometimes dilation
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15
Q

Describe the effects of isometric exercise on the heart

(Isometric exercise = weightlifting)

A

Isometric exercise -> Hypertrophy

  • Mass/volume ratio increases
  • Hypertrophy is the result of increased systemic pressure during exercise
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16
Q

What is the most common cause of myocarditis?

A

Viral

(Coxsackie is the most common viral cause)

17
Q

What is the most common cause of congestive heart failure in the world?

A

Chagas disease

(Caused by Trypanosoma Cruzi, carried by the Reduviid bug)

18
Q

Which bacteria are most likely to cause myocarditis?

A
  • Corynebacterium diphtheriae
  • Mycobacterium tuberculosis
  • Treponema pallidum (Syphillis)
  • Leptospira (Leptospirosis)
19
Q

What is the most common cause of hypertrophic cardiomyopathy?

A

Genetic

20
Q

What causes primary endocardial fibroelastosis?

A

Ischemia/hypoxia in fetal development

Leads to restrictive cardiomyopathy

21
Q

What are the most common causes of secondary cardiomyopathy?

A
  • Toxic/physical
    • Alcohol, cobalt, anthracycline drugs
  • Metabolic
    • Vitamin deficiency
    • Hemochromatosis
    • Hypo/hyperthyroid
  • Storage
    • Glycogen
    • Hunter-hurler
  • Infiltrative
    • Sarcoidosis aka Granulomatosis
      • -> Heart block if in Bundle of His
    • Amyloidosis
    • Tumor
  • Neruomuscular
    • Muscular Dystrophy
    • Friedrich’s Ataxia
  • Inflammatory
  • Collagen Diseases
  • Immune-mediated (hypersensitivity)

[Note: there are individual cards for each sub-group]

22
Q

What are the most common infiltrative causes of secondary cardiomyopathy?

A
  • Sarcoidosis aka Granulomatosis
    • -> Heart block if in Bundle of His
  • Amyloidosis
  • Tumor
23
Q

What are the most common viral causes of myocarditis? (4)

A
  • Coxsackie (most common)
  • ECHO (Enteric Cytopathic Human Orphan) Virus
  • Influenza
  • CMV (in immunosuppressed patients)
24
Q

How can you distinguish between restrictive and constrictive cardiomyopathy?

A

Both have LV diastolic dysfunction

  • Restrictive
    • Reduced compliance is caused by abnormal elastic properties of the myocardium and/or intercellular matrix
  • Constrictive
    • Reduced chamber compliance is imposed by the external pericardial constraint

(http://www.onlinejacc.org/content/67/17/2061​)

25
Q

Describe the effects of isotonic exercise on the heart

(Isotonic exercise = cardio)

A

Isotonic exercise -> hypertrophy

  • Mass/volume ratio stays the same
  • Hypertrophy is the result of adjusting to increased volume due to increased venous return
26
Q

What are the most common toxic/phsical causes of secondary cardiomyopathy?

A
  • Alcohol (1/3 of all Dilated Cardiomyopathies)
  • Cobalt
  • Anthracycline drugs
27
Q

Describe the physical features of dilated cardiomyopathy

(aka congestive cardiomyopathy)

A
  • 4-chamber dilation
    • Due to stretch beyond optimal preload
  • Normal wall thickness
  • Hypertrophy
  • Thrombi
28
Q

How do bacterial infections cause myocarditis?

A

Often, the myocardium isn’t directly infected by the bacteria. However, toxins/other factors secreted by bacteria can damage the myocardium

Ex: C. diptheriae toxin

29
Q

What are the most common metabolic causes of secondary cardiomyopathy?

A
  • Vitamin deficiency
  • Hemochromatosis
  • Hypo/hyperthyroid
30
Q

What are the most common bacterial causes of pericarditis?

A

Pyogeni bacteria

Tubercle Bacili

31
Q

What is a cardiac myxoma?

What are the symptoms?

A

A tumor of the heart (rare)

  • May be in the LA (75%) or mitral valve
    • Impaired LV filling
    • Diastolic murmur that varies with position
    • Ball-like; mobile
  • Benign, surgically treatable
32
Q

What is Dressler’s Syndrome?

A

An immune system response after damage to heart tissue or to the pericardium, from events such as a heart attack, surgery or traumatic injury

(https://www.mayoclinic.org/diseases-conditions/dresslers-syndrome/symptoms-causes/syc-20371811​)

33
Q

What is the definition of a secondary cardiomyopathy?

A

Cardiomyopathy has a recognized, extrinsic cause, or is part of a systemic process

Ex: Toxicity, nutrient deficiency, congenital collagen disorder, etc.

34
Q

What are the most common neuromuscular causes of secondary cardiomyopathy?

A
  • Muscular Dystrophy
  • Friedrich’s Ataxia
35
Q

What is the definition of a primary cardiomyopathy?

A
  • Disease process is intrinsic to the myocardium
  • Unknown or idiopathic cause
  • Not associated with generalized disease processes