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Valvular Diseases
| Question | Answer |
|---|---|
| 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
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