A device for loading a leadless pacemaker onto a catheter-based delivery system includes a distal portion and a proximal portion. The distal portion includes a retention feature configured to receive the leadless pacemaker. The proximal portion is proximal the distal portion and includes a funneling structure opening toward the retention feature. The distal and proximal portions of the device are configured such that, when a distal end of the catheter-based delivery system is brought towards the proximal portion of the loading device and the leadless pacemaker is retained by the retention feature, the funneling structure guides features of the distal end of the catheter-based delivery system through an opening in an attachment feature located at a proximal end of the leadless pacemaker.
