Valvular Disease and Heart Failure

Question 1

how to calculate cardiac output?

Answer 1

stroke volume x heart rate

Question 2

how to calculate stroke volume?

Answer 2

end diastolic volume - end systolic volume

Question 3

how to calculate ejection fraction?

Answer 3

(stroke volume/end diastolic volume) x 100

Question 4

how to calculate mean arterial blood pressure?

Answer 4

1/3(SBP-DBP)+DBP
OR
Cardiac Output (CO) x Systemic Vascular Resistance (SVR) + central venous pressure (CVP)

Question 5

define infective endocarditis

Answer 5

an infection caused by bacteria that enter the bloodstream and settle in the heart lining, a heart valve or a blood vessel

Question 6

common symptoms of infective endocarditis

Answer 6

fever 
malaise
sweats
unexplained weight loss
may be new heart murmur

Question 7

blood tests may show what in a patient with infective endocarditis?

Answer 7

anaemia

raised markers of infection

Question 8

what imaging can be used to help diagnose infective endocarditis?

Answer 8

echocardiogram

transoesophageal echo

Question 9

an echocardiogram can show what in a patient with infective endocarditis?

Answer 9

vegetation
abscess
valve perforation and/or new dehiscence of prosthetic valve. often regurgitation of affected valve

Question 10

why is a transoesophageal echo better than a transthoracic echo in diagnosing infective endocarditis?

Answer 10

it has a higher sensitivity

Question 11

what is Duke’s criteria for infective endocarditis?

Answer 11

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

Question 12

list major criteria for infective endocarditis

Answer 12

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

Question 13

list minor criteria for infective endocarditis

Answer 13

Predisposing heart condition /IV drug use
Fever >38 C
Vasc: emboli to organs, brain
Immuno: glomerulonephritis, Oslers nodes, Roth spots
+ve blood cultures that do not meet specific criteria

Question 14

what is the most common causative bacteria for endocarditis?

Answer 14

streptococcus
enterococci
staph aureus
gram -ve bacteria

Question 15

what cardiac features of decompensation would you look for?

Answer 15

symptoms: SOB, freq coughing, leg/abdo swelling, fatigue

clincal signs: ^JVP, lung crackles, oedema

Question 16

what other features of decompensation would you look for?

Answer 16

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

Question 17

define decompensation

Answer 17

inability of the heart to maintain inadequate circulation

Question 18

what part of the heart does infective endocarditis affect?

Answer 18

Infective endocarditis affects the endocardium, especially the valves of the heart

Question 19

what heart valve is affected most frequently in infective endocarditis?

Answer 19

Aortic valve is affected most frequently (aortic > mitral > right-sided valves)

Question 20

why does infective endocarditis affect the valves more commonly?

Answer 20

formation of a vegetation at valves > change to their thickness or a failure in their ability open + close appropriates > bacteria to attach to the endocardium if underlying damage is present, occurs more frequently at sites of turbulent blood flow

Question 21

why are IV drug users at an increased risk of infective endocarditis?

Answer 21

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

Question 22

increased risk of infective endocarditis is in what populations?

Answer 22

IV drug users
complication of routine surgeries
immunosuppressed individuals
individuals w/ congenital heart defects

Question 23

treatment of infective endocarditis

Answer 23

meds: antibiotics for infection
surgery: may have to remove/replace damaged valves
prophylaxis for those with congenital heart defects

Question 24

define dilated cardiomyopathy

Answer 24

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

Question 25

what does a echocardiogram show in a patient with dilated cardiomyopathy?

Answer 25

dilated left ventricle with reduced systolic function (ejection fraction) and typically global hypokinesis

Question 26

what are common causes of dilated cardiomyopathy?

Answer 26

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

Question 27

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

Answer 27

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

Question 28

how is dilated cardiomyopathy managed?

Answer 28

Medical HF therapy - ACEi, beta-blockers, mineralocorticoid receptor antagonists
fluid overload > diuretics
AF > Anticoagulation
Cardiac devices – cardiac resynchronisation therapy and/or implantable cardioverter defibrillator
Transplant

Question 29

list complications of dilated cardiomyopathy

Answer 29

ventricular or atrial arrhythmias, sudden death, impaired systolic and/or diastolic dysfunction, heart failure