Medical device retention feature

A tether head assembly comprising:

• an inner retainer coupled and extending distally from a distal end of an elongated member;
• an outer retainer defining a channel configured to receive the inner retainer, wherein the inner retainer and the outer retainer define a receptacle configured to receive an attachment member of a medical device;
• a sheath configured to receive the inner retainer and the outer retainer;
• and
• a first locking element disposed on an outer surface of the sheath,
• wherein the tether head assembly is configured to be disposed within a catheter lumen of an elongated body of a delivery catheter, wherein the elongated member is configured to transmit a force from a proximal end of the elongated member to the inner retainer to move the tether head assembly within the catheter lumen of the delivery catheter, and wherein the first locking element is configured to interface with a second locking element disposed within an inner lumen to inhibit unintended movement of the tether head assembly towards a distal end of the elongated body of the delivery catheter.

A catheter comprising:

• an elongated body extending from a proximal end to a distal end along a longitudinal axis, wherein the elongated body defines a catheter lumen extending from the proximal end to the distal end;
• a receptacle extending distally from the distal end of the elongated body along the longitudinal axis, the receptable defining an inner volume configured to retain an implantable medical device, wherein the inner volume is in fluid communication with the catheter lumen;
• and
• a locking collar disposed at the distal end of the elongated body, the locking collar comprising a first locking element, wherein the first locking element is configured to interface with a second locking element on an outer surface of a tether head assembly disposed within the catheter lumen and attached to the implantable medical device to prevent unintended distal movement of the implantable medical device along the longitudinal axis.