Respiratory Disease and Heart Failure

Question 1

What is atrial systole?

Answer 1

Atrial contraction

Question 2

What happens in ventricular systole?

Answer 2

1. Isovolumic / isovolumetric contraction
2. Ventricular contraction
3. Ventricular ejection

Question 3

What happens in atrial diastole?

Answer 3

1. Isovolumic / isovolumetric relaxation

2. Ventricular filling

Question 4

How do you calculate stroke volume?

Answer 4

EDV - ESV

Question 5

How do you calculate cardiac output?

Answer 5

SV x HR

Question 6

How do you calculate ejection fraction?

Answer 6

(SV/EDV) x 100

Question 7

How do you calculate mean arterial blood pressure?

Answer 7

(CO x SVR) + CVP

Question 8

Why do you calculate ejection fraction like that?

Answer 8

Ejection fraction is the volumetric fraction of blood ejected by the ventricle with each contraction. It is commonly given as a percentage (hence multiplication by 100)

Question 9

How can mean arterial pressure be estimated at normal resting heart rates?

Answer 9

MAP = DP + 1/3(SP-DP).

Question 10

What is infective endocarditis?

Answer 10

• infection of the endocardium or vascular endothelium of the heart
• ENDO (inner lining), CARD (heart) ITIS (inflammation

Question 11

What is the pathophysiology of infective endocarditis?

Answer 11

• affects the heart valves
  1. bacteria entering the blood stream and forming ”a vegetation”
  2. (a bacterial infection surrounded by a layer of platelets and fibrin) in the endocardium
  3. Streptococci (20-40 % of cases) are the most common infection

Question 12

what are common symptoms

of infective endocarditis?

Answer 12

• Fever
• malaise
• sweats
• unexplained weight loss

Question 13

what may be found in investigation of infective endocarditis?

Answer 13

-new heart murmur on examination

Question 14

what may be found in blood of infective endocarditis patient?

Answer 14

• anaemia
• raised markers of infection
• blood cultures may isolate a microorganism

Question 15

What would the echocardigam of infective endocarditis show?

Answer 15

1. vegetation, abscess, valve perforation and/or new dehiscence of prosthetic valve
2. regurgitation of the affected valve
3. Transoesophageal echo has higher sensitivity compared with transthoracic

Question 16

What is Duke’s criteria?

Answer 16

set of criteria to determine the likelihood of an individual having infective endocarditis

Question 17

What are the major criteria in duke’s?

Answer 17

1. Persistently +ve blood culture for typical organisms
2. ECHO: vegetation, dehiscence of prosthetic valve, abscess
3. New valvular regurgitation murmur
4. Coxiella burnetti infection

Question 18

What is the minor criteria in duke’s?

Answer 18

1. Predisposing heart condition or IV drug use
2. Fever greater than 38 C
3. Vascular: emboli to organs, brain
4. Immunologic: glomerulonephritis, Oslers nodes, Roth spots
5. Positive blood cultures that do not meet specific criteria

Question 19

What is definitive endocarditis according to duke’s?

Answer 19

-2 major clinical criteria
1 major and any 3 minor clinical criteria
-5 minor criteria
+ ve gram stain or culture from surgery or autopsy

Question 20

What is possible endocarditis according to duke’s?

Answer 20

• 1 major and >1 minor clinical criteria

- 3 minor criteria

Question 21

What is rejected endocarditis according to duke’s?

Answer 21

• Resolution after less than 4 days antibiotic treatment
• No evidence of infection after surgery
• Definite or possible criteria not met

Question 22

What features of heart decompensation would you look for in endocarditis?

Answer 22

Cardiac decompensation
•hortness of breath, frequent coughing, swelling of the legs and abdomen, fatigue
• raised JVP, lung crackles and oedema

Question 23

What are the other complications of endocarditis?

Answer 23

1. Vascular and embolic phenomena
2. (stroke, Janeway lesions, splinter/ conjunctival haemorrhages)
3. Immunological phenomena
4. (Osler’s nodes, Roth spots)

Question 24

What is decompensation?

Answer 24

inability of the heart to maintain adequate circulation

Question 25

What part of the heart does infective endocarditis affect?

Answer 25

endocardium, especially the valves of the heart

Question 26

Which valve is mostly affected in endocarditis?

Answer 26

aortic > mitral > right-sided valves

Question 27

Why is it the aortic valve that is most common affected in endocarditis?

Answer 27

1. formation of a vegetation at the valves of the heart either results in changes to their thickness or a failure in their ability open and close appropriates 2. more common for bacteria to attach to the endocardium if underlying damage is present 3. This occurs more frequently at sites of turbulent blood flow such as the valves of the heart

Question 28

How is infective endocarditis risk different for IV drugs users?

Answer 28

increased risk of infective endocarditis due to repeated injection – potentially exposing their bloodstream to bacteria on the surface of the skin or use of non-sterile needles

Question 29

Why can IV drug users get infective endocarditis?

Answer 29

1. Entry of bacteria into the blood stream is first and critical step in infective endocarditis 2. Increased risk of infective endocarditis is therefore seen in I.V. drug users, but also a complication of routine surgeries such as dental surgery 3. also more common in individuals that are immunosuppressed or have congenital heart defects leading to damaged endocardium

Question 30

What is dilated cardiomyopathy?

Answer 30

characterised by dilated and thin-walled cardiac chambers with reduced contractility

Question 31

Why does dilated cardiomyopathy affect contractility?

Answer 31

1. Dilation of the chambers leads to reduced contractility 2. . Echo shows a dilated left ventricle with reduced systolic function (ejection fraction) and typically global hypokinesis

Question 32

What are the commonest cause of dilated cardiomyopathy?

Answer 32

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

Question 33

What genes have been implicated in the diagnosis of dilated cardiomyopathy?

Answer 33

Mutations in genes encoding cardiac cytoskeletal proteins e.g. Titin, Lamin, Phospholamban, cardiac myosin binding protein C, myosin heavy chain

Question 34

Why do these gene mutations affect dilated cardiomyopathy?

Answer 34

1. A number of genes have been identified to associate with dilated cardiomyopathy 2. Frequently in genes essential for the formation or effective contraction of heart chambers thus either affect myofibril or cellular structure

Question 35

How is dilated cardiomyopathy managed?

Answer 35

1. Medical heart failure therapy - ACE inhibitors, beta-blockers, mineralocorticoid receptor antagonists 2. Diuretics for fluid overload 3. Anticoagulation for atrial fibrillation 4. Cardiac devices – cardiac resynchronisation therapy and/or implantable cardioverter defibrillator 5. Transplant

Question 36

How can dilated cardiomyopathy matter in the future?

Answer 36

at risk of heart failure hospitalization, cardiac arrhythmias, sudden cardiac death due to ventricular arrhythmia, and reduced survival