Interventional medical systems and associated assemblies

A system comprising:

• an implantable medical device comprising:
• a hermetically sealed housing that contains one or more processors for delivering a pacing therapy;
• and
• a projecting member joined to the hermetically sealed housing;
• and
• a tethering system comprising:
• a shaft that extends longitudinally between a distal end and a proximal end;
• an attachment component coupled to the distal end of the shaft, the attachment component defining a receptacle comprising a relief and a secure zone opposing the relief, wherein the secure zone is configured to receive the projecting member of the implantable medical device, wherein the attachment component defines a passageway that provides access to the receptacle and that is narrower than the receptacle, wherein the attachment component is configured to be coupled to the projecting member of the implantable medical device;
• and
• a wire extending in sliding engagement within the shaft between a first position in which a distal most tip of the wire extends into the passageway of the receptacle thereby narrowing the passageway and a second position in which the distal most tip retracts into the receptacle, the wire being moveable from the first position to the second position and from the second position to the first position, wherein at least a portion of a distal segment of the wire is configured to deflect into at least a portion of the relief as the projecting member of the implantable medical device enters the secure zone.