Abstract: A method for subcutaneously implanting a heart device in a patient using an implantation device involves making a first incision in the vicinity of the sternum of the patient and a second incision in the lumbar region of the patient posterior to the vertebral column of the patient. The implantation device is inserted through the first incision to the second incision, and a guidewire is placed through the implantation device via the second incision to the first incision. An end of the guidewire is coupled to the heart device, and the guidewire is pulled through the implantation device until the guidewire is placed within the patient. The guidewire then is detached from the heart device, and the implantation device is removed. The first and second incisions are sutured such that the heart device is left positioned completely subcutaneously around the heart and outside of the ribcage of the patient.