lecture 4/tutorial 5: valvular heart disease

Question 1

What are the 2 key classifications of valve pathology?

Answer 1

Stenosis, regurgitation/incompetence

Question 2

What is valve stenosis?

Answer 2

Failure of a valve to open completely leading to obstruction to blood flow/pressure overload

Question 3

What is valve regurgitation?

Answer 3

Failure of a valve to close completely leading to reversed/retrogade flow and volume overloads

Question 4

What are functional valve pathologies?

Answer 4

Issues with structurally normal valves arising from issues with larger heart structures that transmit to the valves - e.g. ventricular dilation pulling on papillary muscles preventing proper closure

Question 5

What is the effect of valve stenosis on cardiac muscle?

Answer 5

Pressure overload leads to chamber muscle hypertrophy, which later causes failure and dilation

Question 6

What is the effect of valve regurgitation on cardiac muscle?

Answer 6

Chamber dilation, particularly in the atria

Question 7

Which type of valve pathology is most likely to cause atrial fibrillaton, and why?

Answer 7

(mitral) valve regurgitation - causes left atrial dilation which leads to the formation of re-entry pathways causing atrial fibrillation

Question 8

Which valve is most commonly affected by congenital valve disease, and with which pathology?

Answer 8

Aortic valve - stenosis due to congenitally bicuspid aortic valve

Question 9

What is the most common cause of calcific aortic stenosis?

Answer 9

Degeneration with age - 7-9th decades

Question 10

What infection causes rheumatic fever?

Answer 10

Group A streptococcus

Question 11

What is the pathogenesis of Acute Rheumatic Fever?

Answer 11

1. Patient acquires GAS pharyngitis
2. Antibody to M protein in bacteria cross reacts with valve tissue (antigen mimicry), and T cells also cross-react
3. Inflamed heart valves rub together exposing collagen and tissue factor to blood flow
4. Microthrombi/vegetations called verrucae form at the commisssures of the valves.

Question 12

What are the features of valves affected by chronic rheumatic heart disease?

Answer 12

Thickened leaflets, fused comissures, scarring, thick/short chordae tendinae - valve stenosis/incompetence

Question 13

What are the clinical features of rheumatic fever?

Answer 13

pancarditis, migratory polyarthritis, subcutaneous nodules, erythema marginatum, sydenham chorea

Question 14

What valve is most commonly involved in rheumatic fever?

Answer 14

Mitral valve

Question 15

What is the most common valve deformity in rheumatic heart disease?

Answer 15

Mitral valve stenosis

Question 16

What are the effects of rheumatic fever on the rest of the heart, apart from the valves?

Answer 16

Rheumatic pancarditis - endocarditis, myocarditis, pericarditis

Question 17

What are the effects of rheumatic myocarditis?

Answer 17

Causes the myocardium to be soft and flabby, resulting in chamber dilation and heart failure in some cases

Question 18

What examination can help to diagnose rheumatic pericarditis?

Answer 18

Chest auscultation - listen for pericardial friction rub as the layers of inflamed pericardium rub together

Question 19

What are the foci of inflammation in rheumatic myocarditis?

Answer 19

Aschoff bodies

Question 20

What are Aschoff bodies, and what are their constituents?

Answer 20

Foci of inflammation in rheumatic myocarditis. Consist of central necrosis surrounded by lymphocytes and activated macrophages (caterpillar cells)

Question 21

What is the gross morphology of rheumatic pericarditis?

Answer 21

Inflamed pericardial surface has a shaggy fibrin-rich exudate on top - ‘bread and butter pericarditis’

Question 22

What are the names for fused, stenotic fissures in rheumatic heart disease?

Answer 22

button-hole, fish-mouth

Question 23

What is the pathogenesis of subacute infective endocarditis?

Answer 23

1. bacteria enters the blood of a person with previously damaged valves.
2. turbulent blood flow around the damaged valves causes endothelial injury, resulting in microthrombi formation that are easily colonised by bacteria.
3. bacteria cause inflammation forming large friable vegetations

Question 24

What valve is typically affected by infective endocarditis in injecting drug users?

Answer 24

Tricuspid valve

Question 25

What is the key histological feature of vegetations of acute bacterial endocarditis?

Answer 25

Abundant with neutrophils, and are septic (contain bacteria)

Question 26

What valve pathologies cause a diastolic murmur?

Answer 26

Mitral valve stenosis, Aortic valve regurgitation, Tricuspid valve stenosis, Pulmonary valve regurgitation

Question 27

What valve pathologies cause a systolic murmur?

Answer 27

Mitral valve regurgitation, aortic valve stenosis, tricuspid valve regurgitation, pulmonary valve stenosis