Cheney didn't receive a new heart; he received a new ICD (which is both a pacemaker & defibrillator combo). It’s a small device, about the size of a deck of cards, which is implanted in the muscles of the chest (often the peck muscles although it is also placed directly under the skin depending on the surgeon). The device is comprised of a small computer that can not only record heart rhythms, but interpret them and give treatment accordingly and 2 electrodes that connect the device to the heart.
Each device is programmed for the individual patients needs.
The pacemaker sends tiny shocks to the heart that correct certain arrhythmias, maintain a designated heart rate (ex: maintain a heart rate above 60, or maintaining a constant heart rate of 70), and in some patients the pacemaker takes the place of the sinus node and is completely reasonable for creating a heart beat (these are only a few examples).
The defibrillator is the “big gun,” (think ER- socking a clinically dead patients with giant paddles); it can shock a heart that has stopped, or a heart that has entered a dangerous rhythm.
The device is typically monitored by a Cardiologist (who specializes in the electrical system of the heart) every 3 to 6 months. It is called a device “interrogation” (no joke); basically using a special computer the doctor can look at all the data collected by the device- reviewing dangerous rhythms, when treatment has been given, and remaining battery power, doctors can even make changes to the ENTIRE programming of the device with the push of a button.
ICD’s are typically thought of as something thrown in some old guy to keep his ticker going but the truth is that ICD’s are used in all age groups for a multitude of conditions (including congenital heart defects in children). My first device was implanted at age 13 and my most recent 8 days ago.
(battery life typically lasts 4-8 years; often, as with Cheney’s when the battery must be replaced the entire device is changed out. Mostly because within 2 or 3 years the devices have greatly improved and the newer models can offer a lot more and are often smaller)