MHD: Valvular Heart Disease

Question 1

Which heart valves are the semilunar valves?

Answer 1

Aortic and pulmonary

Question 2

Which heart valves are the atrioventricular valves?

Answer 2

Tricuspid and mitral

Question 3

What are the components of the valve apparatus?

Answer 3

Leaflets, annulus, chordae tendinae, papillary muscles, ventricular wall
-Valvular competency depends on the integrity of all of these components

Question 4

What components of valve tissue are visible on histology?

Answer 4

Valve tissue has a connective tissue core (spongiosa, fibrosa, reticularis) made up of collagen and elastic fibers

Question 5

What is a bicuspid aortic valve?

Answer 5

When the (normally tricuspid) valve has only two valves due to incomplete separation during embryogenesis
-This condition causes early aortic stenosis

Question 6

What is the most common valvular abnormality?

Answer 6

Calcification, often due to wear and tear

Question 7

Describe the pathogenesis of calcific aortic stenosis

Answer 7

The aortic cusps are calcified, which prevents the cusps from properly opening and obstructs outflow. This causes an increase in the pressure gradient across the valve leading to left ventricular hypertrophy

Question 8

What are the symptoms of calcific aortic stenosis?

Answer 8

Congestive heart failure
Myocardial ischemia
Syncope

Question 9

How does hypertrophy cause ischemia?

Answer 9

Thicker myocardial walls result in more tissue to perfuse from the same arterial supply. Oxygen diffusion may not be sufficient if the walls become too thick.

Question 10

What happens during mitral valve prolapse?

Answer 10

The mitral valve becomes enlarged and floppy, balloons into the atrium during systole

Question 11

What histological changes are seen in mitral valve prolapse?

Answer 11

Mucoid/Myxomatous deposition within the valvular tissue and thinning of the fibrosa

Question 12

What abnormal heart sound is associated with mitral valve prolapse?

Answer 12

Midsystolic click

Question 13

What rare, but serous complications are associated with mitral valve prolapse?

Answer 13

Infective endocarditis
Mitral insufficiency
Stroke/systemic infarct
Arrhythmias

Question 14

What is infective endocarditis and what is its most common cause?

Answer 14

Destructive inflammation of cardiac valves and endocardium

Most commonly caused by bacterial infection

Question 15

What is a vegetation?

Answer 15

An abnormal outgrowth on the valves of the heart

Typical of endocarditis

Question 16

What are the categories of infective endocarditis?

Answer 16

Acute: emergency with high mortality
Subacute: non-emergency often affecting previously deformed valve

Question 17

Which bacteria are most commonly associated with acute infective endocarditis? Subacute?

Answer 17

Acute: Staph Aureus
Subacute: Strep Viridans

Question 18

What patients are at risk for infective endocarditis?

Answer 18

Patients with valvular disease or prosthetic valves
Immune deficient
Diabetic
IV drug user
Alcoholics

Question 19

What are the portals of entry for infective endocarditis?

Answer 19

Infection elsewhere
Dental procedures leading to bacteremia
Injection of contaminated material into blood
Occult source

Question 20

How is infective endocarditis diagnosed?

Answer 20

Clinical suspicion
Blood cultures
EKG

Question 21

What complications are associated with infective endocarditis?

Answer 21

Cardiac: valve insufficiency/stenosis, abscess, dehiscence or leak in prosthetic valves
Emboli: brain, kidney, spleen, lung
Immune: glomerulonephritis

Question 22

List the lesions associated with infective endocarditis?

Answer 22

Splinter hemorrhage
Conjunctival petechiae
Osler nodes (fingers, tender)
Janeway lesions (feet, not tender)

Question 23

What is the treatment for infective endocarditis?

Answer 23

IV antibiotics
Surgery
Antibiotic prophylaxis for high risk patients

Question 24

What are the major non-infected vegetations?

Answer 24

Nonbacterial thrombotic endocarditis
Endocarditis of systemic lupus
Acute rheumatic fever

Question 25

Describe nonbacterial thrombotic endocarditis

Answer 25

Sterile thrombi form small, non-destructive, loosely attached vegetations
Common in hypercoagulable patients (sepsis, cancer, burns, indwelling catheters)

Question 26

Describe endocarditis of systemic lupus erythematosus

Answer 26

Lupus patients can form small vegetations on the mitral and tricuspid valves due to immune complex deposition
Leads to valvulitis, fibrosis and valve deformity

Question 27

Describe rheumatic fever

Answer 27

Onset: 10 days to 6 weeks after group A strep pharyngitis infection
Pathogenesis: immune cross reactivity between M-protein of strep and the heart leads to immune response against your own heart

Question 28

What are the major manifestations of rheumatic fever?

Answer 28

JONES criteria
Joints: migratory polyarthritis 
Carditis
Nodules: subcutaneous nodules
Erythema marginatum of skin
Sydenham chorea

Question 29

What is the histological hallmark of rheumatic fever?

Answer 29

Aschoff bodies are seen between myocytes

Appear like mini-granulomas containing macrophages and multinucleated cells

Question 30

What is the end result of rheumatic fever?

Answer 30

Chronic rheumatic valvular disease: valves become fibrotic and can fuse, cordae become short, thick and can fuse

Question 31

What valve is most often affected by rheumatic fever?

Answer 31

The mitral valve (65-70% alone)

Question 32

What is a carcinoid tumor?

Answer 32

A neuroendocrine tumor that secretes bioactive products

Question 33

Describe carcinoid heart disease

Answer 33

Plaque like endocardial thickening of the right side of the heart and its valves (mucopolysacharide matrix)
Correlated with 5HT levels

Question 34

What is the most common primary tumor of the heart?

Answer 34

Myxoma (most often of left atrium)

Question 35

What is a myxoma?

Answer 35

A benign gelatinous appearing tumor composed of mucopolysaccharide matrix

• The tumor can form a ball-valve obstruction
• Tumor is at risk of embolizing

Question 36

What is the most common primary pediatric tumor of the heart?

Answer 36

Rhabdomyoma

Question 37

What is an angiosarcoma?

Answer 37

Malignant aggressive endothelial cancer of the heart

Question 38

What is the most common malignancy of the heart?

Answer 38

Cardiac metastases