Just like a human heart, the SynCardia temporary Total Artificial Heart (TAH) is pulsatile and consists of two ventricles and four valves that pump blood throughout the body. The SynCardia TAH is made of a special biocompatible plastic, which offers a high degree of fatigue resistance and strength for long-term durability.
Ventricles
The TAH consists of two artificial ventricles made from biocompatible plastic, which prevents the TAH from being rejected by the body. The ventricles are connected together by Velcro, which allows the surgeon to position the ventricles in the chest based on the patient’s anatomy.
Valves
Each ventricle has two mechanical valves: an inflow valve and an outflow valve. These valves control the direction of blood flow in and out of the ventricle.
Diaphragms
Inside each ventricle is a flexible, balloon-like membrane known as a diaphragm. The diaphragm divides the ventricle into two chambers: a blood chamber, which holds the blood when it enters the ventricle, and an air chamber.
Cannulae & Drivelines
Two tubes called cannulae, which are partially covered in velour to promote healing, connect to the air chambers of the ventricles. The cannulae then exit the body through the abdominal wall and attach to two tubes called drivelines. These drivelines are connected to an external pump known as a driver.
External Driver
The external driver produces pulses of air and vacuum that travel through the drivelines to inflate and deflate the diaphragms, which push blood in and out of the ventricles. The driver runs on batteries and also plugs into a standard electrical outlet.
The SynCardia TAH is a fixed rate device, which means after the beat rate is set, the beats per minute will stay the same, even when your activity level changes. A typical setting is around 125 beats per minute. When you exercise, no adjustments need to be made to the device. Your body will automatically return more blood to the TAH, which will then pump that increased amount of blood back out to your body.
The SynCardia TAH comes in two sizes: 70cc and 50cc. The 70cc TAH fits a majority of men and some women. It is capable of generating blood flow of up to 9.5 liters per minute depending on the patient. The smaller 50cc TAH is designed to fit a majority of women and some adolescents. It can generate blood flow of up to 7.5 liters per minute depending on the patient. In comparison, the average human heart at rest pumps an average of 5 liters of blood per minute.
Yes. A left ventricular assist device (LVAD) is a heart pump that is implanted next to the failing heart and supports the left ventricle only. In contrast, the TAH replaces, and occupies the space of, the removed failing heart and pumps blood through both the left and right ventricles.