A detachment mechanism (10) for an introducer assembly (100) is designed to hold a coupling element (76) of an implantable medical device (70) until its desired release within a patient's vessel. The detachment mechanism (10) includes a body portion (12) having first and second gripper arm elements (14, 16) which grip onto the coupling element (76) of the medical device (70). The gripper arms (14, 16) are naturally biased into a closed position by means of resiliency of the body element (12). For this purpose, an actuating device or opening element (60) is provided which includes an enlarged head (62) which can be pulled against tapering internal surface (32, 34) of the body portion (12) of the detachment mechanism (10) in order to force the gripper arms (14, 16) open, thereby to release the medical device (70) from the introducer assembly (100). The detachment mechanism (10), being naturally in the closed configuration, reliably holds a medical device (70) to the introducer assembly (100) until it is desired to release the latter into the patient's vessel.
