The severity of mitral regurgitation is decided by all of the following clinical findings except –
Correct Answer: Intensity of systolic murmur across mitral valve
Description: Mitral regurgitation (MR), mitral insufficiency, or mitral incompetence, is a form of valvular hea disease in which the mitral valve does not close properly when the hea pumps out blood. It is the abnormal leaking of blood backwards from the left ventricle, through the mitral valve, into the left atrium, when the left ventricle contracts, i.e. there is regurgitation of blood back into the left atrium.MR is the most common form of valvular hea disease.severity is determined by intensity of systolic murmer across mitral valve The degree of severity of MR can be quantified by the regurgitant fraction, which is the percentage of the left ventricular stroke volume that regurgitates into the left atrium. regurgitant fraction = {displaystyle {frac {V_{mitral}-V_{aoic}}{V_{mitral}}}times 100%} frac{V_{mitral} - V_{aoic}} {V_{mitral}} times 100% where Vmitral and Vaoic are, respectively, the volumes of blood that flow forward through the mitral valve and aoic valve during a cardiac cycle. Methods that have been used to assess the regurgitant fraction in mitral regurgitation include echocardiography, cardiac catheterization, fast CT scan, and cardiac MRI. The echocardiographic technique to measure the regurgitant fraction is to determine the forward flow through the mitral valve (from the left atrium to the left ventricle) during ventricular diastole, and comparing it with the flow out of the left ventricle through the aoic valve in ventricular systole. This method assumes that the aoic valve does not suffer from aoic insufficiency. Another way to quantify the degree of MR is to determine the area of the regurgitant flow at the level of the valve. This is known as the regurgitant orifice area, and correlates with the size of the defect in the mitral valve. One paicular echocardiographic technique used to measure the orifice area is measurement of the proximal isovelocity surface area (PISA). The flaw of using PISA to determine the mitral valve regurgitant orifice area is that it measures the flow at one moment in time in the cardiac cycle, which may not reflect the average performance of the regurgitant jet. Ref Davidson 23rd edition pg 455
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