Valvular Disease and Heart Failure

Question 1

How do you calculate cardiac output?

Answer 1

cardiac output = heart rate x stroke volume

Question 2

How can you calculate stroke volume?

Answer 2

stroke volume = end diastolic volume - end systolic volume

Question 3

What is cardiac output?

Answer 3

volume of blood the heart pumps in one minute (L/min or cm3/min)

Question 4

How do you calculate ejection fraction?

Answer 4

ejection fraction = stroke volume / end diastolic volume x 100

Question 5

What is ejection fraction?

Answer 5

the volumetric fraction of blood ejected by the ventricles with each given contraction (%)

Question 6

How can you calculate mean arterial pressure when under stress?

Answer 6

mean arterial pressure = (cardiac output x systemic vascular resistance) + central venous pressure

Question 7

How can you calculate the mean arterial pressure at rest (estimated)?

Answer 7

mean arterial pressure = diastolic pressure + 1/3 (systolic pressure - diastolic pressure)

Question 8

What is infective endocarditis?

Answer 8

infective endocarditis is an infection of the endocardium/vascular endothelium of the heart

Question 9

What causes infective endocarditis?

Answer 9

• bacteria entering the blood stream and forming a ‘vegetation’ in the endocardium
• streptococci (20-40%)

Question 10

What is a ‘vegetation’?

Answer 10

a bacterial infection surrounded by a layer of platelets and fibrin

Question 11

What are the symptoms of infective endocarditis?

Answer 11

• fever
• malaise
• sweats
• unexplained weight loss

Question 12

What may be heard on examination with infective endocarditis?

Answer 12

heart murmur (new)

Question 13

What may blood tests show with infective endocarditis?

Answer 13

• anaemia

- raised infection markers

Question 14

What may blood cultures show with infective endocarditis?

Answer 14

• microorganism

Question 15

What may an ECG show with infective endocarditis?

Answer 15

• vegetation
• abscess
• valve perforation
• dehiscence of prosthetic valve
• regurgitation of the affected valve

Question 16

What are the features of heart decompensation?

Answer 16

Cardiac

• shortness of breath
• frequent coughing
• swelling of legs and abdomen
• fatigue
• raised JVP
• lung crackles
• oedema

Question 17

What are the other complications associated with heart decompensation?

Answer 17

Vascular and embolic phenomena
- stroke
- Janeway lesions
- splinter/conjunctival haemorrhages
Immunological phenomena
- Osler's nodes
- Roth spots

Question 18

What part of the heart does infective endocarditis effect?

Answer 18

endocardium, especially the valves of the heart

- most frequently: aortic valve (mitral, right-sided valves)

Question 19

Why does infective endocarditis tend to effect the valves of the heart?

Answer 19

formation of vegetation is more likely if underlying damage is present - which is more common in sites of turbulent blood flow.

Question 20

How does infective endocarditis differ for IV drug users?

Answer 20

• increased risk due to repeated injection

- entry of bacteria into the blood stream is the first step of development

Question 21

Which populations are at increased risk of developing infective endocarditis?

Answer 21

• IV drug users
• immunosuppressed
• congenital heart defects (damaged endocardium)

Question 22

What is dilated cardiomyopathy?

Answer 22

dilated and thin-walled cardiac chambers with reduced contractility

Question 23

What would an Echo of dilated cardiomyopathy show?

Answer 23

• dilated left ventricle
• reduced systolic function (ejection fraction)
• global hypokinesis

Question 24

What are the common causes of dilated cardiomyopathy?

Answer 24

• idiopathic
• genetic
• toxins (alcohol, cardiotoxic chemo)
• pregnancy (peripartum cardiomyopathy)
• viral infections (myocarditis)
• tachycardia-related cardiomyopathy
• thyroid disease
• muscular dystrophies

Question 25

How is dilated cardiomyopathy managed?

Answer 25

Medical heart failure therapy
- ACEi
- BB
- mineralcorticoid receptor antagonists
Diuretics (fluid overload)
Anticoagulation (A fib)
Cardiac devices
- cardiac resynchronisation therapy
- implantable cardioverter defibrillator
Transplant

Question 26

What are the complications associated with dilated cardiomyopathy?

Answer 26

• heart failure hospitalisation
• cardiac arrhythmias
• sudden cardiac death (ventricular arrhythmia)
• reduced survival

Question 27

What genes are implicated in the diagnosis of dilated cardiomyopathy?

Answer 27

mutations in genes encoding cardiac cytoskeletal proteins (eg: myosin heavy chain, titin, lamin)
- essential for the formation or effective contraction of heart chambers that affect either myofibril or cellular structure.

Question 28

What is part of the major Modified Duke’s criteria to diagnose infective endocarditis?

Answer 28

• positive blood cultures for infective endocarditis (typical micro-organism)
• echocardiographic evidence of valvular regurgitation

Question 29

What is part of the minor Modified Duke’s criteria to diagnose infective endocarditis?

Answer 29

• predisposing heart condition
• IV drug use
• fever
• vascular phenomena
• microbiological evidence
• immunologic evidence

Question 30

According to the Modified Duke’s criteria what is required for definite infective endocarditis?

Answer 30

• 2 major

- 1 major + 3 minor

Question 31

According to the Modified Duke’s criteria what is required for possible infective endocarditis?

Answer 31

• 1 major + 1 minor

- 3 minor