Abstract: A medical device system includes an elongate sheath defining a lumen extending within the elongate sheath. A coupler mechanism is slidingly disposed within the lumen, the coupler mechanism including a proximal coupler and a distal coupler. An elongate member is secured to and extends proximally from the proximal coupler. An implantable medical device (IMD) is secured to and extends distally from the distal coupler. The distal coupler remains secured to the proximal coupler while the coupler mechanism remains within the lumen, and the distal coupler releases from the proximal coupler, thereby releasing the IMD, when the coupler mechanism is exterior to the lumen.