A transseptal medical device is provided including a dilator, a needle, and a needle control mechanism. The needle may be disposed within the dilator, and the needle control mechanism may be operably connected to a proximal end of the needle or the dilator for selective adjustment of the distal end of the needle from a first position within the dilator to a second position external to the dilator. The needle control mechanism may include an actuator configured for rotation within the dilator in one embodiment. In another embodiment, the proximal end of the dilator may incorporate internal threads and the proximal end of the needle may incorporate external threads, such that the needle may be configured for rotation during selective adjustment of the distal end of the needle from a first position to a second position. A method for puncturing a septum of a heart is also disclosed.