Interventional medical systems and associated tethering assemblies and methods

An interventional medical system comprising an implantable medical device and a delivery catheter for deploying the device at an implant site, and the catheter comprising:

• an elongate tubular member extending from a proximal end thereof to a distal end thereof, the tubular member including a lumen that extends from a proximal opening, at the proximal end, to a distal opening, at the distal end;
• and
• a tethering assembly comprising a tether line, a grip member, and a release member, the grip and release members being located distal to the distal end of the tubular member, the release member including a base, a longitudinal lumen extending through the base, and a plurality of legs extending distally from the base and being spaced apart from one another around the base lumen, the grip member including a grip member base, a plurality of apertures formed through the grip member base, and a plurality of elastic fingers extending distally from the grip member base and being spaced apart from one another around the plurality of apertures, each leg of the plurality of legs of the release member extending through a corresponding aperture of the grip member base and having a distal end configured to secure the release member to the grip member, the tether line extending through the lumens of the tubular and release members, being in sliding engagement within both lumens, and the tether line including a distal end coupled to the grip member base;
• and
• wherein the elastic fingers of the grip member define a cavity of the grip member, the cavity being sized to receive a proximal end of the device therein, the fingers being configured to hold the device proximal end within the cavity, and each finger being deformable to allow insertion and withdrawal of the device proximal end into and out from the cavity;
• each leg of the release member extends into the grip member cavity and is in sliding engagement within the corresponding aperture of the grip member base to move from a first position in the cavity to a second position in the cavity, the first position at which the distal ends of the release member legs and the device proximal end both fit within the grip member cavity, and the second position at which the release member legs extend further into the grip member cavity so that the proximal end of the device does not fit therein;
• and
• the release member legs are moved from the first position to the second position when increased tension in the tether line pulls the grip member proximally relative to the release member.