An operator can release a looped portion of a tethering member, which terminates a distal section thereof, from being secured within a locking lumen of a delivery catheter shaft, and then move the distal section out of engagement with an attachment feature of an implantable medical device to untether the device from the catheter. The tethering member extends within another lumen of the shaft, which may be part of a catheter assembly that further includes a locking member extending within the locking lumen and having a distal tip located in proximity to an aperture of the shaft. To tether the device to the catheter, the operator can engage the tethering member distal section with the device attachment feature, and then pass the looped portion thereof through the aperture and into the locking lumen, where the locking member distal tip can be passed through the looped portion to secure it.
