Valvular Heart Disease Flashcards
(34 cards)
Symptoms of Heart Failure
- Pitting oedema
- Sacral oedema
- Raised JVP
- Ascites
What does N-terminal Brain Natriuretic Peptide measure?
Natruretic - reduction of salt and water
When cardiac myocytes are stressed they produce the above peptide reducing the blood pressure.
By measuring the peptide you can measure if the heart is under stress
What is the difference between aortic stenosis and aortic regurgitation?
Aortic stenosis: heard in systole - Narrowing of aortic valve, restricting blood flow from the left ventricle to the aorta
Aortic regurgitation: heard in diastolic, the aortic valve doesn’t shut properly so blood flows back from the aorta into the left ventricle during diastole
What are the causes of Aortic stenosis
- Degenerative - mechanical stress over time damages the endothelial cells causing fibrosis & calcification
- Bicuspid Valve (congenital)- more mechanical stress per leaflet
- Rheumatic Heart Disease - repeated inflammation leading to fibrosis, leaflets can fuse together
What are the causes of Aortic Regurgitation?
Acute
1. Idiopathic aortic root dilation
2. Aortic dissection
3. Aneurysms
4. Infective endocarditis
Chronic
1. Rheumatic fever
2. Bicuspid aortic valve
3. Degeneration
4. Connective tissue disorders e.g. Marfans
What are the symptoms & examination findings of aortic stenosis
Ejection-systolic murmur in a Crescendo-decrescendo pattern in the 2nd intercostal space.
Ejection Click
Radiates to the Carotids
Symptoms - Extertional syncope, Angina, Dyspnoea, Fatigue, Heart Failure symptoms
What are the symptoms & examination findings of aortic regurgitation
Diastolic murmur with an early decrescendo. Heard best at the left sternal edge (4th intercostal space), with the patient leaning forward.
Doesn’t radiate
Symptoms; Externtional dyspnoea, orthopnoea, paroxysmal nocturnal dyspnoea, pulmonary oedema
What is the Pathiohysiology of Aortic Stenosis
- Narrowing of aortic valve means blood flow across the aortic valve is impeded during systole
- Left ventricle has to generate higher pressure to push blood past hardened valve
- This results in concentric left ventricle hypertrophy
- Over time the left ventricle can no longer compensate and the left ventricle starts to enlarge so the ejection fraction will reduce and this will lead to reduced cardiac output
- Eventually, leading to heart failure
What Investigations should you do to confirm a murmur?
Echo
CXR
ECG
Cardiac Catheterisation
Exercise Stress Test
How do you manage Aortic Stenosis?
- The majority of patients with mild aortic stenosis will never progress to developing clinically significant aortic stenosis
- Monitor with echocardiogram to assess valve; Severe AS monitored every 6 months
Mild-to-moderate monitored yearly
Younger patients monitored every 2 to 3 years - If patients develop symptoms of heart failure, may be given ACE inhibitors, diuretics, and beta-blockers
Surgical and interventional indicated in: - All patients with symptomatic AS
- Asymptomatic patients with a left ventricular ejection fraction (LVEF) <50%
- Asymptomatic patients with an LVEF >50% who are physically active, and who have symptoms or a fall in blood pressure during exercise testing
What are the 2 main types of Valves for replacement?
- Bioprosthetic: lasts 10 years so may require another replacement but no need for long term anticoagulant therapy
- Metal: last a lifetime but require long-term anticoagulant therapy (warfarin)
What is the pathophysiology of Aortic Regurgitation?
- Blood leaks from aorta into the left ventricle during diastole
- Therefore, with each contraction, the LV must pump the regurgitant volume plus the normal quantity of blood from the left atrium
- In acute AR the left ventricle is normal size, so the volume load of regurgitation causes the LV diastolic pressure to rise
- In chronic AR, the LV undergoes compensatory adaptation through eccentric hypertrophy in response to excessive pressure load
- The dilation increases the compliance of the left ventricle so it can accommodate a larger volume of blood
- Compensatory left ventricular dilation and hypertrophy can meet the demands of chronic AR for many years meaning patients are asymptomatic
- However, eventually as the LV increases in size, this leads to systolic dysfunction which leads to heart failure
What is the management of Aortic Regurgitation?
- Asymptomatic patients are monitored year and echocardiography performed every 2 years
- Asymptomatic patients but with severe AR may need vasodilators: calcium channel blocker, ACE inhibitor to treat accompanying hypertension
- Symptomatic or asymptomatic with severe AR (LVEF <55%) offered surgery
o Valve replacement
o TAVI is not recommended unless patient has high surgical risk
What are the 2 types of heart murmur?
- Innocent murmurs: These are typically soft, systolic murmurs without associated symptoms or abnormal physical findings. They are commonly heard in children and adolescents and do not require further evaluation or treatment.
- Pathological murmurs: These can be further classified based on timing (systolic, diastolic,
continuous), location (aortic, pulmonary, tricuspid, mitral), radiation, and associated
symptoms
What is Infective Endocarditis?
Infective endocarditis is an infection of the inner surface of the heart, usually affecting the heart valves. It can be caused by a wide range of organisms that can cause high or low virulent infections.
Discuss the pathophysiology of Infective endocarditis
- endocardial surface injury
- platelet-fibrin-thrombus formation at the site of injury
- bacterial entry into circulation
- bacterial adherence to injured endocardial surface
The organisms are then free to multiply, which enlarges the infected vegetation. The latter provides a source for continuous bacteraemia and can lead to several complications.
Discuss the presentation of infective endocarditis
- Very variable & can be difficult to diagnose
- Vague malaise to a ‘devastating’ acute presentation
- Malaise, anorexia, weight loss, aches & pains
- Vasculitic rashes
- Splinter haemorrhages & petechial rash referred to as peripheral stigmata of endocarditis
- Murmur – original lesion & valve erosion
- Glomerulonephritis
- Splenomegaly, clubbing, pigmentation – long term infection so rare
- Osler’s nodes, Janeway lesions & Roth spots
What are major complications of infective endocarditis?
- Systemic embolism – from vegetation breaking off
- Heart failure – damage to valve
- Cerebrovascular;
Embolism
Infected aneurysm – mycotic aneurysms
What different Bacteria cause Endocarditis
Viridans streptococci
Staph A
Staph Epidermidis
Coxiella burnetti
Candida albicans
HACEK organisms - gram negative bacteria from normal flora of mouth & throat
Haemophilus, Aggregatibacter, Cardiobacterium, Eikeneela, Kingella
What microorganism is suspected in IE following dental work?
Viridans Streptococci
Attacks previously damaged valves
Found in mouth, low virulence
What microorganism is suspected in IE following IV drug use?
Staph A
Infects damaged & healthy valves & can destroy valves
Found on skin, high virulence
Can also be fungal - Candida albicans
What microorganism in IE is associated with severe colorectal disease?
Staph epidermidis
infects prosthetic material
Enters body during valve surgery or IV catheter
What microorganism that causes IE is associated with infected animals
Coxiella burnetti
Normally only seen if immunocompromised
Discuss investigations of Infective endocaridits
Bedside investigations:
ECG – prolonged PR interval. This suggests the development or worsening of aortic root abscess
Urine dip – looking for haematuria which could suggest glomerulonephritis
Bloods
Elevated inflammatory markers
If its subacute or chronic there may be normocytic anaemia present
Blood cultures – 3 different blood cultures much be taken at different times and sites
Imaging
Echocardiogram
CT – can look for any septic emboli
