Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Q. Pathology of mitral regurgitation?
During left ventricular systole as the pressure rises in left ventricle, blood is pumped simultaneously both into aorta and left atrium. The effective orifice that allows regurgitation is called effective regurgitant orifice. The fraction of total left ventricular stroke volume that regurgitates in to left atrium is regurgitant fraction. In chronic mitral regurgitation compliant left atrium dilates and accommodates the regurgitant blood thus not allowing the mean left atrial pressure to rise. As the blood flow across mitral valve increases during next diastole, end diastolic volume of left ventricle increases. With increased pre load, left ventricular ejection fraction increases and maintains forward stroke volume in spite of regurgitation. During systole as the left ventricle is open to low pressure left atrium, afterload decreases. Thus in chronic mitral regurgitation left ventricular ejection fraction is more than normal due to increased preload and decreased afterload. As the mitral regurgitation progresses, left ventricle and left atrium dilate. Dilated large left atrium will have areas of fibrosis leading to generation of atrial fibrillation. Dilated chambers with dilated mitral annulus and altered geometry of papillary muscles and posterior left atrial wall lead to aggravation of mitral regurgitation. Hence mitral regurgitation begets mitral regurgitation. Eventually changes take place in left ventricular myocardium causing myocardial dysfunction. As stated earlier, increased preload and decreased afterload of left ventricle allow maintained left ventricular ejection fraction even in the presence of myocardial dysfunction. Left ventricular ejection fraction is not a load independent index of left ventricular systolic function and is not suitable to assess left ventricular systolic function in patients with chronic mitral regurgitation. Removal of the regurgitant orifice through which left ventricle has a low pressure outlet by mitral valve replacement or repair will effectively increase the afterload. Failing myocardium will now face afterload mismatch and left ventricular ejection fraction actually decreases after surgery. Understanding this concept is of fundamental importance in timing of mitral valve surgery.
Define Unintentional Adulteration - Types of Adulteration? These are the contaminations occur unknowingly or incidently in the food during harvesting, handling, transportation,
Define Importance of Nutrition in Human Body? Nutrition is increasingly being recognized as an important determinant, which modulates the biological process of ageing. Poor nut
locomotion in protozoa
The allele that causes albinism (p) is recessive to the allele for normal pigmentation (P). A normal woman whose father is an albino marries an albino man whose parents are both no
Why doesn't gene therapy cure cystic fibrosis? Although a normal gene is introduced into a patient's surface cells in the lung, these cells are not the ones that require produc
Q. What are the secondary and the primary constrictions of a chromosome? And what is the other name given to the secondary constriction? Primary constriction is the narrower re
Q. How are the epithelial tissues classified? The epithelial tissues are classified according to the shape of the cells that form it epithelial cells may be columnar, cuboidal,
What are the general symptoms of brain tumors The general symptoms of brain tumors, which result from increased intracranial pressure, include headache, vomiting, swelling of t
Q. Factors Affecting Normal Blood Sugar Levels? Earlier in our discussion, we learnt that insulin is the most important factor responsible for normal blood sugar levels. Now we
Cilia and Flagella – Protozoans Cilia and flagella basically have a similar structure and distinction between the two on structural basis does not exist. There is a filament o
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd