Loud S1 in Mitral stenosis is seen in-

Ans. is 'a' i.e., Prolonged flow through mitral valve Siis louder in Mitral stenosis because AV flow is prolonged. The loud Si in mitral stenosis usually signifies that the mitral valve is pliable and that it remains open at the onset of isovolumetric contraction because of the elevated left atrial pressure. S1 can be soft even in the presence of mitral stenosis, when the anterior mitral leaflet is immobile and rigid due to calcification.