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Valvular Diseases

QuestionAnswer
The circulatory system is a _________ system. closed
Pressure changes will go in both directions if permitted to do so. Valves do what? Valves are the only things keeping blood flowing in the direction its supposed to flow.
Reduction of volume in chamber increases what? pressure.
*Ideally, valves keep blood flowing in the correct direction without interfering with the flow. :)
Problems with the valves cause problems in two ways: 1) regurgitation - blood flows backward. 2) stenosis - blood flow is impeded.
Valve problems ultimately lead to what? more work for the heart - and that is bad.
Regurgitation is due to a ________________ valve. An incompetent valve.
Stenosis is due to an ____________ valve. Interfering valve.
Causes of most valvular problems: (5) 1) We have outlived the valves. 2) Result of rheumatic fever. 3) Congenital defects. 4) Infections of the heart. 5) Atherosclerosis.
What bacterium leads to rheumatic fever? Streptococcal infections of head/throat can lead to rheumatic fever, usually during childhood.
What causes rheumatic fever? (3) Not really sure of the causes, but it may be 1) hyper-immune response to strep. 2) direct damage caused by strep on tissues. 3) immune response theory - antibodies developed against strep reacting also against self.
What happens in the first round of rheumatic fever? What happens in the other rounds? First round - does no damage. After first exposure, you're more likely to get rheumatic fever and they cause more damage.
What is one problem with the effects of rheumatic fever? they take years/decades to appear. Over time, valves become sclerotic and calcified, which affects their performance (you want them flexible and strong).
Most valve diseases hit the __________ valve. Second most common hits the _________. Why? Mitral; then aortic semi-lunar. this is because the left side of the heart deals with relatively higher pressures.
Does mitral stenosis deal with pressure or volume? Pressure issue.
What is a problem getting blood from the left atrium to the left ventricle during diastole? Mitral stenosis.
In a normal heart, is there a pressure difference between the LV and the LA? The ventricle is, after all, ___________ and _____. No, there should be no real pressure difference. The ventricle is expanding its lumen and sucking blood from the atrium.
In Mitral Stenosis, the atrium does what? Hypertrophies and dilates to push blood through the mitral better.
What is thickening of the myocardium? Concentric hypertrophy. muscle growing thicker.
What is thinning/elongation of the myocardium? Eccentric hypertrophy. muscle growing lengthwise.
In mitral stenosis, pressure backs up into the _______________ all the way to the ______ which does what? What is the result? In mitral stenosis, pressure backs up into the pulmonary circulation all the way to the right ventricle, which hypertrophies too. This results in pulmonary congestion and hypertension.
Over time, what happens to the diameter of the mitral valve opening in mitral stenosis? It is reduced.
What is a hallmark of mitral stenosis? Why? Dyspnea on exertion. Dyspnic because lungs are filled with fluid. Not getting enough oxygen to the body.
Explain the general process of mitral stenosis: Brain yells at heart if blood is not getting to tissues. Heart then squeezes blood through atrium, which causes a pressure gradient (should never have pressure gradient). Pressure begins to go back to pulm. vein and caps, etc...
What is the net perfusion pressure in the lungs and the pulmonary capillaries combined? 1 mm Hg - net perfusion pressure.
A greater pressure in the lungs and pulmonary capillaries causes what? Fluid accumulation in the lungs. Now right ventricle is having to work harder than normal. Pressure goes back to the RV and then into systemic circulatory system.
Is mitral regurgitation a volume or pressure thing? Volume thing.
What happens in mitral regurgitation? Left ventricle has to push blood into aorta AND back into atrium - more work. This is caused by an incompetent mitral valve.
Initially, what does the heart do to compensate for mitral regurgitation? Ventricle and atrium can hypertrophy (eccentric hypertrophy) to accommodate the need to push more volume of blood out (increased stroke volume).
When LV and LA lose the ability to compensate, what happens? they dilate - which causes problems of its own (too much stretching is bad for muscles). Pressure feeds back on pulmonary circulation.
Dilation = __________ of heart muscle = _________________. Dilation = stretching = heart failure.
What is the difference between dilation and eccentric hypertrophy? Eccentric hypertrophy is the heart growing lengthwise. dilation is the stretching of the heart muscle which will cause heart failure.
volume changes cause the heart to remodel. What happens when the heart remodels too often? Heart muscles stretch and the cell proteins begin to detach. Lose contractility force of heart - causes heart failure.
What is aortic stenosis? What does this cause? Fights flow of blood from LV to aorta during systole. This causes a big pressure gradient between LV and aorta.
What happens in response to aortic stenosis? Ventricular hypertrophy (deals with the situation for a long time). when LV can no longer keep up, you get angina, syncope, LV failure and can die.
what is aortic regurgitation (AR)? Peripheral R is low in aortic regurgitation, but later R rises, increasing backward flow into LV. LV contraction must account for normal volume plus the amount that comes back each cycle.
how does the body compensate for aortic regurgitation? Dilation of LV. hypertrophy deals with problem for a long time, but then gives up.
What is the hallmark for tricuspid valve disease? increase in venous pressure. (swelling of veins, edema in the periphery, distention of the liver, ascites).
What is a mixed lesion? both regurgitation and stenosis occur. happens a lot.
what is a combined lesion? Involvement of multiple valves - happens a lot in rheumatic fever. (all the valves are experiencing issues)
what is the treatment for rheumatic fever? Acute rheumatic fever (palliatively) is treated with abx, anti inflammatories and analgesic. Chronic can be treated with prophylactic abx.
Drug treatment for mitral valve disease: Diuretics. Digoxin (increases force of heart contractility). Valvotomy (procedure to clean out valves).
What is the treatment for aortic valve disease? No med treatment available. Must repair the valve by surgery. Needs to be done pretty quickly.
Surgical treatments for mitral valve disease: Treated by valvotomy, or replacement when regurgitation and/or stenosis get too bad.
What are two types of valve replacements? 1) mechanical. 2) tissue
Mechanical Valve replacement: durable, but thrombogenic. Require anticoagulative therapy for lifetime of patient (good for young people).
Tissue valve replacement: Don't last as long as mechanical, but don't cause clots. Valves from pigs and cows or valves from people (cryopreserved from folks who don't need them anymore)
Created by: sam_melillo