Valves, malformations & endocarditis Flashcards
what are the right valves
pulmonary
tricuspid
what are the left valves
aortic
mitral/bicuspid
why are the left valves more likely to fail
they are at the highest pressure.
what are the two ways valves can fail
stenosis
incompetence
what is stenosis
the valve cannot open properly and so doesn’t allow blood through properly
what is incompetence
when the valve cannot close properly
what does a valve problem lead to
increase the risk that the patient will develop heart failure therefore when someone has a valve that does not work properly they must be replaced with a prosthetic one before permanent damage to the heart occurs thus early treatment is important!
how can an MI lead to valve problems
Heart valves are little cusplets of collagen and they are attached to the papillary muscles through tendons called chordinae tendinea
The papillary muscles keep the valves under tension and keep it shut. If you have an MI then this can cause damage to the papillary muscles and end up with valve function problems
if the mitral valve does not open properly what does it lead to
it causes an increase in pressure in the atrium and a lack of blood in the ventricle causing a decreased cardiac output and an increase in pressure in the pulmonary system.
what happens in rheumatic heart disease
the body forms an antibody against bacteria, but it also targets the tissue of the heart valve due to having the same protein structure which causes damage to the valves.
what can cause valve disease
congenital abnormality
myocardial infarction
rheumatic fever
dilation of the aortic root
how does congenital abnormality lead to valve disease
o Formed incorrectly during development
o Cannot do the job you want it to do
o Bicuspid aortic valve instead of normal tricuspid aortic valve
how does MI cause valve disease
o Papillary muscle rupture
how does rheumatic fever lead to valve disease
o Immunological reaction to streptococci
how does dilation of the aortic root lead to valve disease
o If you dilate the aortic root then it is stretched and the valve gets pulled apart so cannot do their job – issue here is not to do with the valve but with the aorta
o Syphilis
o Aneurysm formation
how can you investigate valve disease
ultrasound of the heart
dye allows for better assessment
can see different directions of blood
if working properly should be moving only in one direction
what is the most common valve replacement
Valve replacements are generally mechanical, they are made in a workshop and will essentially be made of metal.
what is the advantage of mechanical valve replacement
long lasting
what is the disadvantage of mechanical valve replacement
lifetime of anticoagulants
why do pig valves not attract clots
they contain the normal collagen leaflets
who are pig valves used for
those in extremes oof life
what do those with valve replacements have risk of
endocarditis
what is a congenital heart defect
These happen as the embryo is forming
It is the failure of the fusion of the heart
what is an ASD
When there is overfusion of the atria there is a hole from the left to the right side of the atria however the atria is a low pressure system and the differences in pressures is not great so for many cases the effect is not noticeable
what are VSD
in the ventricles and these are a high pressure system and there is a difference between the left and right. When the left ventricle contracts some of the blood goes through to the right ventricle increasing the workload of the right side which can lead to right sided heart failure. You need to repair most VSDs
what is ductus arteriosus
a bypass between pulmonary circulation and systemic circulation because an unborn child does not need to use their lungs
what is patent ductus arteriosus
failure of closure of arteriosus
what are congenital heart defects
ASD
VSD
patent ductus arteirosus
great vessel malformation
what is cyanosis
exists when there is 5g/dl or more of deoxygenated Hb in the blood
makes it difficult to get enough oxygen to the tissues and you go blue if you have it
what is central cyanosis due to
due to congenital heart disease – people with this are blue all over, even in tissues that are usually pink.
what is peripheral cyanosis
Peripheral cyanosis is due to the cold environment
what is finger clubbing
Much not understanding of it but causes swelling in the terminal tissues of the fingers – due to chronically low blood levels of oxygen
what happens in VSD
Portion of the blood in the left ventricle is going to the right ventricle and it going back through the pulmonary artery into the lungs.
The left ventricle is having to work harder to maintain the CO and the right ventricle is having to work harder to deal with the increased volume
what happens in correction of the aorta
When the baby is born a deep breath is taken causing a pressure difference in the lungs meaning that it is better to go through the pulmonary artery than the aorta and as oxygen level builds up and the oxygen tension goes up the ductus shuts. Sometimes the closing goes onto the aorta and results in a narrowed aorta making it difficult to carry blood through the aorta.
what happens in patent ductus arteriosus
If it remains open it goes through the aorta and back to the lungs and it can lead to heart failure.
what are those with congenital abnormalities more at risk of
endocarditis – guidance from a cardiologist is required.
What is endocarditis
infection of the endocardium
usually on the valves
How does infective endocarditis happen
microbial colonisation of thrombi on endocardial surface abnormalities
What are predisposing factors for endocarditis
rheumatic fever less common now
prosthetic valves more common now
