Figure 1. Early Model Artificial Heart (Source)
Brief: The artificial heart has long been considered one of the holy grails of modern medicine. Although earlier technology has made it difficult for the heart to be replaced simply because of physical and mechanical limitations, with advancements in medical technology it is now possible to be implanted with an artificial heart that can last for a few years before replacement. The first artificial heart was made by Vladimir Demikhov in 1937 and implanted into a dog. However, because of compatibility issues, it was unable to be used in humans. Later, with changes to the heart itself including the valves and materials, the first heart for human use was invented in 1969.
Figure 2. Jarvik-7 Artificial Heart (Source)
The artificial heart is generally comprised of a series of titanium and assorted plastics such as polyurethane. These materials are considered to be generally biocompatible with the human body because of their inert non immune reaction. Along with the housing, a number of electronic components are also placed within the heart. Additionally, the heart must be able to handle fluid blood flow without forming any clots. The pump which operates the motor must be efficient enough that it generates minimal heat into the body. Lastly, to avoid rejection from the host body, the heart must be small (~660 mL) and lightweight (1.2 kg). As these constraints are very difficult to accomplish, the heart has not yet been completed and a multitude of companies are continuing research on it. These companies include: Phoenix-7, Abiomed, Berlin Heart, MagScrew, SynCardia, Frazier-Cohn, Carpentier/CARMAT, and POLVAD. In modern times, the artificial heart can be implanted into the body for upwards of 3 or 4 years before replacement.
Figure 3. Circular Continuous Centrifugal Heart Pump (Source)
Use: The artificial heart is usually implanted into the body and allowed to run on its own. During open heart surgery, the surgeon will often reroute the patient's bloodflow through an external heart pump. Afterwards, the patient just simply continues his or her own life and comes in for routine checkups to monitor progress. Most recipients of artificial hearts are those who are unable to continue waiting for a heart transplant donor. The artificial heart would then buy them more time so that they may be able to wait for a proper donor. However because this technology is still undergoing progress, there are number of varieties. Additionally, there are centrifugal and axial pump options. This removes the patient's pulse but they are still alive.
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