The development of artificial hearts has made a significant difference in the lives of many heart-compromised victims. When it comes to a standard heart transplant, it is very difficult to match the recipient with a viable donor heart. For a donor heart to be viable, it must be taken from a patient with no brain activity that is still surviving via life support. There are many in-depth tests conducted on tissues and blood to ensure that the new heart is a likely match and to ensure that the recipient will be able to receive a new heart.
Until recently, patients with dysfunctional or severely damaged hearts faced a heart transplant as their only possible path to a long life; however, there are only approximately 2,000 heart transplants performed annually in the United States, leaving many more thousands of patients facing potential death each year. New technology has developed artificial hearts that provide transplant patients with a new avenue to life.
HOW ARTIFICIAL HEART TECHNOLOGY WORKS
An artificial heart is a type of man-made mechanical device that replaces the human heart in a patient’s body. The average human heart beats 60 to 100 times per minute with the right and left atria pumping blood to their respective ventricles at the same time. The ventricles then contract together to push blood out of the heart and into the body.
These man-made heart technologies perform the same process, but slightly differently. Whereas the human heart’s atria work simultaneously, a man-made heart pushes blood out of one ventricle at a time, alternating sides. This results in the heart pushing blood out to the lungs and then to the body, rather than to both at the same time as is done with a natural human heart.
Beyond the heart – or pump – there are several additional pieces of technology that must all work together to keep the artificial heart functioning.
Wireless Energy-transfer System: This system contains two coils that send power from an external battery across the skin (without piercing the surface) using a magnetic force. One of the coils is internal, whereas the other is external. The internal coil will receive the power and transmit it to an internal battery and controller device (two additional system components). This wireless energy-transfer system is also called a transcutaneous energy transfer – or TET, for short
Internal Battery: A rechargeable battery is implanted inside the patient’s abdomen. This battery provides the patient with a 30-40-minute window that they can disconnect from the main battery pack, allowing them to do certain things such as taking showers
External Battery: This rechargeable battery provides approximately four or five hours of power between charges and is worn around the patient’s waist on a Velcro belt pack
Controller: The controller is a small electronic device that is implanted into the patient’s abdominal wall and controls and monitors how fast the heart is pumping
On the whole, this man-made heart system weighs approximately two pounds. The artificial heart is made from plastic and titanium and connects to the right and left atriums, aorta, and pulmonary artery.
ARTIFICIAL HEART TRANSPLANT PROCEDURE
The man-made heart transplant procedure is an open heart surgery that requires the chest to be opened in order to operate on the heart muscle, valves, arteries, or other areas of the heart such as the aorta or vessels. This surgery takes approximately seven hours to complete due to the in-depth, complex process of not only removing the existing heart but replacing it with a man-made technology that needs to be manually connected and tested to ensure a proper fit and functionality.
An anesthesiologist will administer general anesthesia to put the patient into a deep sleep, ensuring they do not wake during the course of the surgery or experience any pain. The surgeon will make a long incision down the chest before opening the breastbone to access the heart; at this point, the patient will be put on a heart-lung machine.
The heart-lung machine is a standard technology used for on-pump surgeries; it temporarily pumps oxygen-rich blood to the organs and tissues as is usually done by the heart. This requires the surgeon to operate on a non-beating heart without blood actively pumping through it.
Cardiac Surgeons then remove very specific portions of the native heart before placing the artificial heart to garner a proper fit and placement. The surgeons then develop grafts and connect the new heart to the body. The patient is taken off of the heart-lung machine, allowing the new device to fill with blood; at this point, the surgeons can confirm whether the new heart is functioning properly.
Recovery time varies greatly by patient depending on the patient’s condition before the surgery. The hospital stay following surgery may last one month or even longer. Following heart surgery, the patient can expect to remain in the intensive care unit for several days before transitioning to a standard hospital room.
Once home, transplant patients will be able to do many more “standard” activities than they could before the procedure, such as getting dressed, moving freely around the house, and – potentially, even driving.
Patients can bathe or swim as long as internal batteries are charged. They will need to attend regular checkups with their medical team following the surgery to ensure the device is functioning properly and that recovery is progressing. Ongoing medication is necessary to prevent blood clotting and infections.