Device Components

There are several parts of the SynCardia TAH-t system.

SynCardia (TAH-t) Ventricles

The TAH-t pump replaces the sick or weak heart ventricles. The TAH-t pump has two chambers—an air chamber and a blood chamber—that are separated by a membrane. The air chamber connects to the cannula and driver, which pushes air in and out. The air moves the membrane in the correct position to fill and eject the blood chamber. On the blood chamber side, the blood enters and exits the chamber.

TAH-t Pump
C2 Hospital Cart
C2 Driver Caddy
Freedom Portable Driver

There are two different TAH-t pump sizes: 50 cc and 70 cc. The 50 cc pump is generally used in children and small adults. The 70 cc pump is used in bigger people. Prior to surgery, the care team will review your testing to determine which size device is appropriate for your body size.


The two cannulae come out of the body above the belly and connect the right and left TAH-t pumps to the Companion 2 Hospital Driver (C2). 

Companion 2 (C2) Driver (Hospital Cart & Caddy) or Freedom® Portable Driver (Freedom Driver)

The C2 driver  is a large machine that pushes air in and out of the TAH-t pump. While in the hospital, the hospital cart is most often used. It shows all of the settings and will allow your care team to make any changes. There are also waveforms that help the team determine how well the device is working. For hospital mobility, the C2 driver caddy may be used as well.  

The Freedom Driver is a small machine used if you are eligible for discharge from the hospital. It fits in a backpack and allows for more mobility.

Electrical Power

The batteries for the C2 driver usually last approximately 1 and a half hours. The Freedom Driver batteries last approximately 4 hours and can be recharged through either a standard electrical outlet or a car charger.

Pump Parameters

There are many numbers that you will see on the screen of your SynCardia TAH-t:

  • Heartrate: The rate at which the device is set to beat/eject blood to the body.
  • Fill Volume: The amount of volume that fills the ventricles with each beat. For the 50 cc device, the fill volume should be around 30–40. For a 70 cc device, the fill volume should be 50-60 ml. Generally, the amount of volume in the ventricle should only fill 2/3rds of the device.
  • Left and Right Pressure: The amount of air pressure that the device uses to pump blood to the lungs and body.
  • Percent Systole: The percentage of time that the device spends ejecting the blood.
  • Cardiac Output: The amount of blood that is ejected to the body.
  • Left and Right Vacuum: The amount of air pressure needed to pull back the membrane and fill the blood chamber. This is always a negative number.


Alarms can be loud and scary, but they are designed to let us know when something is not working properly. There is no need to panic when you hear an alarm. Your care team will review the steps that you or your caregiver can take to correct the problems.