5.4 - Valvular disease and heart failure

Question 1

What is infective endocarditis?

Answer 1

• infective endocarditis is an infection of the endocardium or vascular endothelium of the heart
• typically affects heart valves
• usually the result of bacteria entering the bloodstream and forming a ‘vegetation’ in the endocardium

Question 2

What is a vegetatation?

Answer 2

A bacterial infection surrounded by a layer of platelets and fibrin

Question 3

What is the most common infection causing infective endocarditis?

Answer 3

Streptococci (20-40% of cases)

Question 4

How do you diagnose infective endocarditis? (6)

Answer 4

• fever, malaise, sweats and unexplained weight loss are common symptoms
• there may be a new heart murmur on examination
• blood tests show anaemia and raised markers of infection
• blood cultures may isolate a microorganism
• echocardiogram can show a vegetation, abscess, valve perforation and/or new dehiscence of prosthetic valve
• often regurgitation of affected valve

Question 5

What kind of echocardiogram has a higher sensitivity for infective endocarditis?

Answer 5

Transoesophageal echo has higher sensitivity compared with transthoracic

Question 6

What are the major criteria of Duke’s criteria for infective endocarditis? (4)

Answer 6

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

Question 7

What are the minor criteria of Duke’s criteria for infective endocarditis? (5)

Answer 7

• predisposing heart condition or IV drug use
• fever >38
• vascular - emboli to organs, brain
• immunologic - glomerulonephritis, Osler’s nodes, Roth spots
• positive blood cultures that do not meet specific criteria

Question 8

What indicates definite endocarditis using Duke’s criteria?

Answer 8

• 2 major clinical criteria
• 1 major and 3 minor clinical criteria
• 5 minor criteria
• +ve gram strain or culture from surgery or autopsy

Question 9

What indicates possible endocarditis using Duke’s criteria?

Answer 9

• 1 major and >1 minor clinical criteria
• 3 minor criteria

Question 10

What rejects endocarditis using Duke’s criteria?

Answer 10

• resolution after <4 days antibiotic treatment
• no evidence of infection after surgery
• definite or possible criteria not met

Question 11

What is the definition of decompensation?

Answer 11

Inability of the heart to maintain adequate circulation

Question 12

What features of heart decomposition would you look for in infective endocarditis - cardiac decompensation?

Answer 12

• symptoms include shortness of breath, frequent coughing, swelling of legs and abdomen, fatigue
• clinical signs include raised JVP, lung crackles and oedema

Question 13

What features of heart decomposition would you look for in infective endocarditis - other complications?

Answer 13

• vascular and embolic phenomena
  
  • stroke, Janeway lesions, splinter/conjunctival haemorrhages
• immunological phenomena
  
  • Osler’s nodes, Roth spots

Question 14

What part of the heart does infective endocarditis affect?

Answer 14

• affects the endocardium, especially the valves of the heart
• aortic valve affected most frequently (aortic > mitral > right-sided valves)

Question 15

Why does infective endocarditis affect the valves more?

Answer 15

• formation of a vegetation at the valves either results in changes to their thickness or a failure in their ability to open and close appropriately
• more common for bacteria to attach to the endocardium if underlying damage is present, which occurs more frequently at sites of turbulent blood flow e.g. valves

Question 16

Why are intravenous drug users at higher risk of infective endocarditis?

Answer 16

• repeated injection potentially exposes their bloodstream to bacteria on the surface of the skin
• use of non-sterile needles
• entry of bacteria into bloodstream is first and most critical step in infective endocarditis

Question 17

Who else may be at increased risk of infective endocarditis?

Answer 17

• could be a complication of routine surgeries e.g. dental surgery
• more common in immunosuppressed or those with congenital heart defects leading to damaged endocardium

Question 18

What is dilated cardiomyopathy?

Answer 18

Characterised by dilated and thin-walled cardiac chambers with reduced contractility - dilation of chambers leads to reduced contractility

Question 19

What does an echo show for dilated cardiomyopathy?

Answer 19

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

Question 20

What are the commonest causes of dilated cardiomyopathy? (8)

Answer 20

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

Question 21

How is dilated cardiomyopathy managed? (5)

Answer 21

• medical heart failure therapy - ACE inhibitors, beta-blockers, mineralocorticoid receptor antagonists
• diuretics for fluid overload
• anticoagulation for atrial fibrillation
• cardiac devices - cardiac resynchronisation therapy and/or implantable cardioverter defibrillator
• transplant

Question 22

What are the implications of dilated cardiomyopathy on the future?

Answer 22

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

Question 23

What is the difference between heart failure with preserved ejection fraction and heart failure with reduced ejection fraction?

Answer 23

• HF with preserved ejection fraction - EF > 50%, presence of diastolic/right heart dysfunction –> increased reservoir of blood in the pulmonary veins –> increased pulmonary hypertension and pulmonary oedema
• HF with reduced ejection fraction - EF < 50%, impaired left ventricular systolic function –> pulmonary oedema secondary to impaired systolic function and blood flow via aorta –> backflow of blood into pulmonary veins and lungs (–> pulmonary oedema)

Question 24

What are the clinical signs and symptoms of right vs left heart failure?

Answer 24

• right heart failure - peripheral oedema e.g. leg swelling, raised JVP
• left heart failure - pulmonary oedema

Question 25

What medications are used to treat heart failure with preserved ejection fraction? (2)

Answer 25

Diuretics and SGLT-2 inhibitors

Question 26

What medications are used to treat heart failure with reduced ejection fraction? (6)

Answer 26

• ACE inhibitors (ACEi)
• angiotensin II receptor blockers (ARBs) e.g. preformulated in Entresto
• beta blockers
• mineralocorticoid receptor antagonists
• SGLT-2 inhibitors
• diuretics

Question 27

How is heart failure monitored?

Answer 27

• clinical signs and symptoms of fluid overload - shortness of breath, leg swelling, orthopnoea (needing extra pillow at night), reduced exercise tolerance due to shortness of breath
• observations - low oxygen saturation
• biomarkers - NT-proBP
• imaging - echocardiogram

Question 28

What genes are implicated in the diagnosis of dilated cardiomyopathy?

Answer 28

• mutations in genes encoding cardiac cytoskeletal proteins e.g. Titin, Lamin, Phospholamban, cardiac myosin binding protein C, myosin heavy chain
• frequently in genes essential for the formation of effective contraction of heart chambers thus affect myofibril or cellular structure