Composite detachment mechanisms

An assembly for delivering an implantable device in a body, comprising:

• an implantable device;
• a delivery device, with first and second electrically conductive members extending distally from the delivery device, wherein the first electrically conductive members comprises a distal end terminating in a first distinct ring structure and the second electrically conductive member comprises a distal end terminating in a second distinct ring structure, wherein first and second distinct ring structures are spaced apart from one another;
• and
• a composite detachment mechanism comprising a polymer strand secured to the implantable device, the polymer strand comprising a detachment portion coated with an electrically conductive material and threading through the first and second distinct ring structures and between the first and second electrically conductive members, such that energy conducted from the first conductive member to the second conductive member via the electrically conductive coating material heats and melts the detachment portion of the polymer strand to release the implantable device from the delivery device.