New Artificial Heart Has No Pulse

Diagram of Human HeartOne of the most amazing and awe-inspiring machines man has ever encountered. It requires very little energy to run. It can operate continuously for many decades, even as much as a century or more with absolutely no maintenance required and no breakdowns. It can run safely and with no wear or tear even when operating at maximum capacity for extended periods of time. Without it you couldn’t survive for more than a few minutes.

The human heart.

Yes, there are genetic flukes, heart conditions and other factors that can wear the heart down or cause it to fail, but compare the reliability of the human heart to any machine man has ever made in his history. What if your heart was only as reliable as your average american made car? What if you had to get a new one every 5-10 years? Or if it required a tune-up every 20,000 steps or every 3 months.

There simply isn’t any man-made machine that can match the efficiency, portability, and reliability of the human heart. The only real replacement is well… another heart. Since healthy hearts, that are no longer needed by their original owners, are relatively hard to come by, the natural idea would be to create an artificial one.

Two doctors from the Texas Heart Institute seem to have come pretty close to doing just that. Yes, a completely portable, completely effective artificial heart.

What is most impressive about this new invention is that it approaches the problem from a completely different angle, shattering all of the past fixed ideas of how an artificial heart should operate.

To really understand the magnitude of this discovery you should understand a little about the history of the artificial heart.

While the idea of an artificial heart has probably gone back a long time, an early reference is the 1911 pulp comic super hero with an artificial heart (Nyctalope) invented by French science fiction writer, Jean de la Hire.

Heart and Lung Machine

Heart and Lung Machine replacing the action of the heart

The very first machine that attempted to replace the action of the heart is the Heart and Lung machine, used successfully for the first time in 1953. It was not meant as a replacement but, rather, as a bypass of the heart and lungs so they could be operated on during surgery.

It operated by siphoning blood out of the body, exposing it to oxygen in a fake “lung” and then sending it back into the body.

The problem with this device is that it requires constant attention by an operator to keep the blood properly oxygenated, and was difficult to operate. Imagine literally determining the life or death of someone with your own hands. Not a responsibility taken lightly.

Also, the machine actions damage the blood, destroying many of the red blood cells. However, its a small price to pay when it means a successful life saving surgery.

But this was just the first stage of developement.

Jarvik – 7

Jarvik 7 Artificial HeartThe Jarvik 7, named after its inventor, Dr. Robert Jarvik, attempted to emulate the human heart’s pumping motion. It uses two flexible “balloons” that are compressed with air. An external air compressor pumps air into the device to compress  the balloons alternately, which pushes the blood through the body just like the heart. It was approved for permanent use in 1981.

The Jarvik 7 still requires a large external console and an operator to monitor the pulse speed and pressure, but it was the most successful heart replacement machine of its time permitting many patients to survive the wait needed for a transplant to arrive.

With the large console required though this device is still not a truly workable artificial heart.

The problem being faced was how to create a device that could pump blood the way the heart does that will be reliable for years to come after being installed, won’t require constant maintenance and will also be portable, allowing the patient to live a normal life instead of being chained down to a giant console.

The basic problem being run into is creating a device that pumps blood like the heart, with it’s familiar rhythm. That requires complex machinery. The more complex the machinery the more likelihood that it will wear down or break. Wearing down or breaking is something an artificial heart simply can’t be allowed to do.

No Pulse Artificial Heart

Artificial Heart with No Pulse The latest artificial heart solves all of these problems. It is portable, efficient and it has such a simple operating mechanism that it is completely reliable because there are no complicated parts to wear down.

The thing that sets this device apart from its predecessors though is that it produces NO pulse. That’s right, no more heartbeat. If you were to put your fingers in the traditional position on the wrist of a person who has had one of these devices installed, you would feel a constant humming of flowing blood instead of the typical “thump-thump” of a heart beat.

The genius of this device actually goes back to the 3rd century B.C. with the “Archimedes Screw” which is basically a giant screw used to pull water out of low-level water sources in order to pour it into irrigation ditches.

(See the animation below).

By rotating this screw within a similar sized tube, water is pulled out of the river. This same principal powers the new “turbine” heart.

 

Archimedes Screw showing the action of the artificial heart

Besides the simple and efficient design, the turbine heart is also portable. The device is completely contained inside the body, except for the two external batteries which are each about the size of an old VHS tape.

It is interesting to note that according to a great article on this same device published in Popular Science, the inventors, Dr. Bud Frazier and Dr. Billy Cohn of the Texas Heart Institute, have kept one of these devices operating in a lab for over 8 years now with no maintenance or breakdowns, to test its longevity.

Because of that longevity, the new turbine heart has been approved for use in humans, although only as a temporary measure while the patient is awaiting a real heart for transplant. Eventually, it could be approved for permanent use. However, this new advance allows patients needing a heart transplant the ability to live their normal life with their family and friends, instead of being chained down to hospital beds next to machine consoles, waiting. Truly a giant leap forward in medical science, although it raises many questions.

The heart beat is one of the most iconic aspects of the human body. Poetry and art for millenia have been dedicated to the human heart. What are the cultural implications of having  no heart beat?

While initial evidence demonstrates that there are no negative effects connected to having no pulse, what will we see down the road?

The body is designed to accommodate the constant rhythm of the heart. Will the absence of this rhythm throw other things off that we don’t fully understand, creating other problems in their wake?

On the other side, the beating of the heart is constantly putting variable levels of pressure on the organs and tissues. In any mechanical device, this kind of action would cause faster wear and tear than a device that used a constant pressure.

Could it be the same for the body? Theoretically, with a constant blood flow, less stress would be put on the body. Would a person in such a case age slower and live longer than the same individual with a regular heart?

What do you think?

– David Pulcifer

Science! @ The Auditorium