BIOM 4180 Study Guide - Winter 2018, Comprehensive Midterm Notes - Protein Kinase A, Heart Failure, Adrenergic Receptor
12 Oct 2018
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Department
Course
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BIOM 4180
MIDTERM EXAM
STUDY GUIDE
Fall 2018
Lecture 1: Heart Valves
• Blood flow thru the heart (review)
o Inferior and Superior Vena Cava -> Right atrium -> tricuspid valve -> right ventricle -> pulmonary
valve -> pulmonary artery ->lungs -> pulmonary vein -> left atrium -> mitral valve ->left ventricle ->
Aortic valve -> aorta
o 4 valves in total
▪ 2 atrioventricular valves (tricuspid and mitral valves)
▪ 2 semilunar valves (aortic and pulmonary)
o Valves are made of leaflets/cusps that cover the opening (opening = annulus)
▪ Atrioventricular valves are anchored to the ventricles by chorea tendonae, which prevents
the valves from prolapsing
▪ Prolapse = open in the other direction
• 2 types of valvular disease
o Regurgitation: valve isn’t fully closed, so blood moves backwards
▪ There is a normal amount of regurgitation, but it should not be excessive
▪ In the following slide, there are 2 images
• In the left image, you can see 3 obvious leaflets, and there is obvious overlap
• In the right image, there are 4 leaflets, and there is a hole in the intersection of
the leaflets
▪ Causes
• Genetics
• Infections (bacterial and viral)
• Chordae Tendonae is damaged, and doesn’t close the valve properly
o If the valve prolapses (opens in the other direction) instead of being
shut, blood will move backwards
▪ Treatment of regurgitation
• 1. Regurgitation due to small leaflets
o The leaflets are too small, and aren’t covering the entire opening
o This might happen when the heart undergoes hypertrophy (grows
bigger)
▪ The muscles and chambers grow bigger, but the leaflets don’t
o An annuloplasty ring can just make the annulus (the valve opening) just
a little smaller
▪ Now, the leaflets cover the entire annulus!
• 2. Regurgitation due to stretched chordae tendonae
o If the chordae tendonae are stretched, the leaflets will flutter into the
other chamber (prolapse), leading to regurgitation
o Since the chordae tendonae can’t be shortened, “artificial chordae
tendonae” are placed to hold the valve leaflets in
▪ Suture wires – expanded polytetrafluoroethylene (ePTFE)
o Putting in an annuloplasty right to make the annulus smaller can also
help prevent the leaflets from prolapsing
o Stenosis: the valve can’t fully open, so less blood flows through
▪ Usually due to stiffness of leaflets
▪ Often times, one of the 2 or 3 leaflets refuses to move
• The leaflet itself is usually damaged, and the leaflet thickens in response
• When a leaflet is too thick, it doesn’t move back and forth (flutter) like it’s
supposed to, and may stay closed or open
o If it stays open, blood can move backwards! Stenosis causing
regurgitation
▪ Pacemaker lead wires can easily puncture the mitral valve, leading to thickening of the
leaflet and subsequently stenosis
▪ Critical Foetal Aortic Stenosis
• Baby is born with a stenotic valve
o The valve isn’t opening, and blood isn’t getting to the left ventricle
▪ The left ventricle ends up underdeveloped and weak
o Since the left ventricle pumps blood to the aorta and the rest of the
body, it is supposed to be very strong
• Traditionally, this condition needs to be detected before birth and then operated
on right at birth
find more resources at oneclass.com
find more resources at oneclass.com
o The right ventricle is arranged to take over the left ventricle’s job, along
with it’s original job of pumping blood to the pulmonary system
o The right ventricle can’t keep up this heavy workload for too long, and
the patient will need a heart transplant eventually
• New treatment method
o Correct the stenosis in utero
o Use echocardiography to guide all movement
▪ Very important to include this in your answer!!
o A needle is inserted through the maternal abdomen, uterine wall, and
fetal chest
o A wire containing a balloon is passed through the needle
o The wire is guided to the aortic annulus, and the balloon is expanded
▪ At the aortic annulus, there used to be a stenotic valve that
wouldn’t open
▪ After expanding the balloon at the aortic annulus, the opening
is now clear, and blood can pass through
▪ The left ventricle will develop properly because it is getting
blood
▪ After birth, the aortic valve will have to be replaced, but this is
better than having to do the whole
▪ Adult aortic stenosis
• Can be managed with medication (blood thinners)
• Surgery is available, but is it worth it to do on someone who’s 85?
o Not just a cost-benefit issue, but also a question if the patient can
survive the surgery
o The surgery has traditionally been open chest, which is very stressful for
the patient
o Young children are another group of patients who might not be able to
survive the surgery!!
• NEW SURGERY TREATMENT OPTION AVAILABLE!!
o Trans-catheter aortic valve implantation/replacement (TAVI/TAVR)
o Steps
▪ 1. The valve is mounted around a balloon delivery catheter
▪ 2. The balloon is guided to the heart by echocardiography and
fluoroscopy
• Very important to mention this when answering
questions
• Access through the femoral vein
• If you want to get to the mitral valve instead of the
tricuspid, you will need to puncture the septal wall
▪ 3. When the balloon/valve is at the stenotic valve, inflate the
balloon, which inflates the valve
• The old stenotic valve gets pushed to the sides
• And the new valve gets put in place
• Spring loaded lock holds the valve in place
o Less complicated than open heart surgery
▪ Easier to do, and patient outcomes are better
o More cost effective than open heart surgery
o Can this be brought to the mitral valve too???
▪ It’s a bit harder, since to get to the mitral valve, you’d have to
pass the aortic valve first if you are coming from the left side of
the heart
▪ You can try going from the right side of the heart, and
puncturing the septum (slide 16 diagram)
▪ Melody valves
• Interesting valve that can stretch slightly!!
• Very valuable for paediatric patients
o Their heart grows as they age
o But traditional valves do not
o So every so often, these patients need to go thru surgery again to
replace the valve
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Lecture 1: heart valves: blood flow thru the heart (review) Inferior and superior vena cava -> right atrium -> tricuspid valve -> right ventricle -> pulmonary valve -> pulmonary artery ->lungs -> pulmonary vein -> left atrium -> mitral valve ->left ventricle -> 2 types of valvular disease: regurgitation: valve isn"t fully closed, so blood moves backwards. There is a normal amount of regurgitation, but it should not be excessive. In the following slide, there are 2 images. In the left image, you can see 3 obvious leaflets, and there is obvious overlap. In the right image, there are 4 leaflets, and there is a hole in the intersection of the leaflets: causes, genetics, chordae tendonae is damaged, and doesn"t close the valve properly. If the valve prolapses (opens in the other direction) instead of being shut, blood will move backwards.
