Long back, mitral stenosis (narrowing of the valve between the left atrium and left ventricle) used to be treated by a surgery known as closed mitral valvotomy in which the surgeon used to open the chest and introduce a mechanical device to enlarge the narrowed valve through the tip of the left ventricle. Currently this procedure has become obsolete and almost extinct with the development of balloon mitral valvotomy (BMV). In this procedure, balloon at the tip a long tube (balloon catheter) is used to enlarge the narrowed valve. The balloon catheter for this procedure is introduced through the femoral vein in the groin under local anaesthesia. It moves up the inferior vena cava into the right atrium. Entry from right atrium to left atrium is preformed using a needle and dilated by a dilator introduced through the femoral vein prior to introduction of the balloon tipped catheter. From the left atrium, the balloon is introduced into the left ventricle, across the narrowed mitral valve. Once it is positioned across the mitral valve, the balloon is inflated using dilute radiocontrast to achieve enlargement of the narrowed mitral valve. The whole procedure is guided by X-ray fluoroscopy and is done in a cardiac catheterization laboratory, by trained personnel. When all precautions are strictly followed, balloon mitral valvotomy has a low complication rate and good success rate, making it an acceptable procedure in most cases of mitral stenosis. Some valves which are tough to open up using a balloon because of calcium deposition may still require surgery to either open it up (open mitral valvotomy) or replacement (mitral valve replacement).