A kit for implanting an implantable medical device within a patient, the kit comprising: the implantable medical device; the implantable medical device comprising a housing; a set of active fixation tines attached to the implantable medical device, wherein the active fixation tines in the set are deployable from a spring-loaded position in which distal ends of the active fixation tines point away from the implantable medical device to a hooked position in which the active fixation tines permeate patient tissue, in use, and bend back towards the implantable medical device, wherein the proximal ends of the tines remain fixed to the housing when the tines move from the spring-loaded position to the hooked position and vice-versa and wherein the tines provide a column strength great enough to resist buckling from the force of patient tissue before distal ends of the tines permeate the patient tissue; and wherein the active fixation tines are configured to secure the implantable medical device to a patient tissue when deployed while the distal ends of the active fixation tines are positioned adjacent to the patient tissue; a catheter forming a lumen sized to receive the implantable medical device and hold the active fixation tines in the spring-loaded position, wherein the lumen includes an aperture that is adjacent to the distal end of the catheter; and a deployment element (210, 212) configured to initiate deployment of the active fixation tines while the implantable medical device is positioned within the lumen of the catheter, wherein deployment of the active fixation tines while the implantable medical device is positioned within the lumen of the catheter causes the active fixation tines to pull the implantable medical device out of the lumen via the aperture that is adjacent to the distal end of the catheter. the implantable medical device; the implantable medical device comprising a housing; a set of active fixation tines attached to the implantable medical device, wherein the active fixation tines in the set are deployable from a spring-loaded position in which distal ends of the active fixation tines point away from the implantable medical device to a hooked position in which the active fixation tines permeate patient tissue, in use, and bend back towards the implantable medical device, wherein the proximal ends of the tines remain fixed to the housing when the tines move from the spring-loaded position to the hooked position and vice-versa and wherein the tines provide a column strength great enough to resist buckling from the force of patient tissue before distal ends of the tines permeate the patient tissue; and wherein the active fixation tines are configured to secure the implantable medical device to a patient tissue when deployed while the distal ends of the active fixation tines are positioned adjacent to the patient tissue; a catheter forming a lumen sized to receive the implantable medical device and hold the active fixation tines in the spring-loaded position, wherein the lumen includes an aperture that is adjacent to the distal end of the catheter; and a deployment element (210, 212) configured to initiate deployment of the active fixation tines while the implantable medical device is positioned within the lumen of the catheter, wherein deployment of the active fixation tines while the implantable medical device is positioned within the lumen of the catheter causes the active fixation tines to pull the implantable medical device out of the lumen via the aperture that is adjacent to the distal end of the catheter.