Do you know are mitral regurgitation and mitral stenosis the same thing?

Different. The mitral valve sits between the left atrium, which receives blood from the lungs, and the left ventricle, which pumps blood to the body. Mitral regurgitation is "backleak" of blood from the left ventricle back to the left atrium. Mitral stenosis is restricted opening of the valve, partially blocking blood flowing from the atrium to the ventricle. Both can exist in the same patient.