A total artificial heart is a medical device that replaces the two main pumping chambers of a failing human heart. It is used when both ventricles can no longer move enough blood to keep the body alive. The device connects to the major blood vessels and pushes blood to the lungs and the rest of the body.
It matters because continuous circulation delivers oxygen and removes carbon dioxide and waste from tissues.
Key Facts
- Cardiac output is the blood flow per minute: CO = stroke volume x heart rate.
- A total artificial heart replaces both ventricles, not the atria or the blood vessels.
- The right pump sends oxygen-poor blood to the lungs through the pulmonary artery.
- The left pump sends oxygen-rich blood to the body through the aorta.
- Blood pressure is produced when the pumps apply force to blood inside flexible chambers or sacs.
- Power and control signals usually come from an external driver connected through lines that pass through the skin.
Vocabulary
- Total artificial heart
- A total artificial heart is a device that replaces both lower pumping chambers of the heart to maintain blood circulation.
- Ventricle
- A ventricle is a lower heart chamber that pumps blood out of the heart.
- Cardiac output
- Cardiac output is the volume of blood pumped by the heart or artificial heart each minute.
- Aorta
- The aorta is the large artery that carries oxygen-rich blood from the left side of the heart to the body.
- External driver
- An external driver is the outside power and control unit that keeps some artificial heart pumps moving.
Common Mistakes to Avoid
- Thinking a total artificial heart is the same as a pacemaker is wrong because a pacemaker sends electrical signals to a natural heart, while a total artificial heart replaces the heart's pumping ventricles.
- Labeling the pulmonary artery as carrying oxygen-rich blood is wrong because it carries oxygen-poor blood from the right pump to the lungs.
- Forgetting that the device needs continuous power is wrong because a stopped pump would quickly stop circulation and threaten the brain and other organs.
- Using only heart rate to describe blood flow is wrong because total flow also depends on stroke volume, so CO = stroke volume x heart rate.
Practice Questions
- 1 A total artificial heart ejects 70 mL of blood per beat from the left pump and beats 90 times per minute. What is the cardiac output in L/min?
- 2 An external battery can supply 180 Wh of energy, and the driver uses 12 W of power. How many hours can the battery run the device if energy losses are ignored?
- 3 Explain why a total artificial heart must have separate right and left pumping paths instead of one single pump for all blood flow.