Additional Study Information: The purpose of this study is to find out if the mitral valve can be safely replaced using a procedure that issimpler than the open-heart procedure being used today and may be safer for patients who are at ahigher risk from conventional open-heart surgery. The device being studied would be implanted without the need for an open-heart procedure and without the need for a heart and lung machine. This is thefirst research study for this device that will be carried out in a small number of subjects. This study is being done to learn initial information about the basic safety and function of this device.