Mitral stenosis is due to thickening and immobility of the mitral valve leaflets, resulting in obstruction in blood flow from the left atrium to the left ventricle. The mitral valve leaflets are thickened and the commissures are fused along with thickening and shortening of the chordae tendineae. This mechanical obstruction leads to increases in pressure within the left atrium, pulmonary vasculature, and right side of the heart, in comparison, the left ventricle is unaffected if there is pure mitral stenosis.