What is an artificial heart, how is it made, and how does it work?

What is an artificial heart?

A normal heart contains two pumps and each contains two chambers, and the right atrium pumps blood that does not contain oxygen from the body to the right ventricle. The right ventricle pumps blood to the lungs, and then the left atrium sends the oxygen-saturated blood from the lungs to the left ventricle, which, in turn, pumps blood to all parts of the body.

With each heartbeat, the atria contract together and this contraction is followed by contraction of the large ventricles

Congestive heart failure, which is a decrease in the heart's ability to pump blood, is one of the leading causes of death.

This disease is caused by several factors, including sudden damage caused by a heart attack, from a viral infection, or by high blood pressure.

According to the American Heart Association, an estimated five million Americans suffer from heart failure. More than 400,000 new cases of illness are diagnosed each year and nearly 50% of all patients die within five years

Heart disease cost the US Department of Health about $ 95 billion in 1998 alone.

Although medications and surgical techniques can help control symptoms, the only treatment for heart failure is a new heart transplant.

In 1998, there were about 7,000 Americans on the waiting list for a heart transplant, but only 30% of them got a new one

Thus artificial hearts and auxiliary pump devices were developed as possible alternatives.

What is an artificial heart and how does it work?

The artificial heart maintains the heart's blood circulation and oxygenation for different periods of time

And the ideal artificial heart would have to beat 100,000 times every 24 hours without oiling or maintenance required.

The artificial heart must have a stable energy source and must pump quickly or slowly depending on the patient’s activity without causing any infection or blood clots.

The two main types of artificial hearts are:

1. Heart lung machine
2. The mechanical heart

The first type consists of an oxygenator and a pump and is used to keep blood flowing as the heart works and the heart functions. This machine only works for a few hours and the blood may become corrupted after a while.

As for the second type, the mechanical core was designed to reduce the load applied to the core, which could not work at its normal capacity.

These hearts consist of equipment that pushes blood through the heartbeat or use the artificial reserve ventricle for assistance (left ventricular assist device, LVAD). These devices usually lead to complications that harm the patient, but they are used as temporary alternatives until it is possible to obtain a normal heart for transplantation.

About 4,000 LVADs have been implanted, and these devices are estimated to be consumed at $ 12 billion annually in the United States.

A History of Industrial Hearts

Since the late nineteenth century, scientists have attempted to develop a mechanical device that can supply oxygen to the blood by removing excess carbon dioxide from it. It took nearly 100 years before the first successful industrial heart machine was used on humans. This was done by John H. and Gibbon Jr. in 1953.

The Artificial Heart Program was established in 1964 and this led to the first artificial heart in human use and implantation in 1969. Then the scientists' focus shifted to LVADs and biocompatible materials for humans in the 1970's. Pumping devices continued to be developed and became smaller, lighter and more acceptable

During the 1980s, the Food and Drug Administration (FDA) imposed more restrictive rules for the Medical Device Standards Act, resulting in higher development costs. This prompted many research groups in this field to withdraw, with only a few remaining to the present day.

The most famous scientist is Dr. Robert Jarvik, who invented an artificial heart called Jarvik-7. This device was made of aluminum and plastic.

Where the two lower chambers were replaced by the natural core and a rubber fender was used to do the pumping with an external compressor.

The artificial heart was kept in a very cold atmosphere and there was a patient named Barney Clark, who was the first person to receive this heart. He survived 112 days before developing physical complications from the transplant that led to his death.

In 1986, patient William Schroeder became the second recipient of the artificial heart, Jarvik 7, and survived for 20 months. And the medical community realized at the time that the transplanted heart could be improved and avoided the symptoms and infection which are the problems caused by Jarvik-7.

In 1988 the National Institutes of Health began funding research into artificial hearts. This program was supported in 1991 with an amount of $ 6 million. And after three years it became possible to implant an electronic LVAD device with a power supply

In 1999 Charlie Chappis became the first patient outside the hospital to carry this device.

Raw materials used in the manufacture of the heart:

The artificial heart is made of materials such as metals, plastics, and ceramics, and titanium and aluminum sheets are used in the heart pump because they have suitable structural properties.

For titanium sheets, they are cut by a processor dedicated to titanium and shaped into precise parts.

As for the blood contact surfaces, they are coated with a special coating of titanium microscopic parts, and the blood contact surface membrane inside the pump is made of a special type of polyurethane and is designed to provide adhesion to blood cells.

The two tubes are made of polyester and are used to connect the device with the aorta

Artificial Heart Design:

There are several critical issues when designing an LVAD

The dynamic fluid of blood flow must be understood so that blood is pumped sufficiently without clots occurring. Materials that are bio-acceptable must be selected otherwise the core can fail, and the efficiency of the motor must also be improved so that the minimum heat is set.
The overall size and surface area should be kept as small as possible, for example an LVAD model weighing about 2.4 pounds.

Collection:

Each artificial core takes several days to put its pieces together and test, and the assembly process is carried out in a clean room to avoid contamination.

The artificial core consists of 50 components, which are assembled together using special adhesives, and these adhesives are processed at high temperatures.

Packaging :

After testing, the artificial heart is sent to sterilization and then returned to the factory to be packed in a dedicated box to protect it from contamination and prevent damage.

Quality control :

Most components go through an inspection before they reach the core plant and some components are subject to a lot of scrutiny because they require very high precision mechanical tolerances and special measuring tools.

The future of artificial hearts:

Within the next decade, many new devices will be introduced to the market

Researchers at Pennsylvania State University are developing an electromechanical core powered by radiofrequency energy that travels through the skin.

Nowadays, artificial hearts are being tested and developed in various designs.