Balloon valvuloplasty is a procedure used to open a narrowed heart valve. It is performed on children who have a condition called stenosis (a narrowed valve in the heart). The goal of this surgery is to improve valve function and blood flow by enlarging the valve opening. Balloon valvuloplasty is sometimes used to avoid or delay open heart surgery and valve replacement. During the procedure, a thin tube (called a catheter) with a small deflated balloon at its tip is inserted through the skin in the groin area and into a blood vessel. Then, the catheter is threaded up to the opening of the narrowed heart valve. The balloon is inflated in order to stretch the valve open and relieve the obstruction inside the valve. The procedure may take up to four hours and is performed in a cardiac catheterization laboratory that is equipped with a special X-ray machine and an X-ray monitor.