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Posted by on Jun 1, 2012 in Science |

The source: The artificial heart

The source: The artificial heart

in the Montreal Centre (cc) flickr thehoneybunny

The is the most important organ of the circulatory system and muscle a human being fundamental to life. Perhaps because of the perfection with which the human body evolved, occupies the center of the chest, right between the lungs and behind the sternum, the bone that protects like a sentinel of all accidents.

This vital organ has a continuous operation and in case of stop, is only a matter of seconds for which the owner runs out of life. But the complex and precise machinery of this body as powerful and transcendent, has been a major source of inspiration for scientists and physicians for nearly 80 years have felt attracted to emulate it artificially.

Although the heart is conceptually a simple organ, and it is considered a muscle that functions like a pump, pushing blood through the body, has become a matter of great challenges in of the last century , who encouraged by this seemingly simple structure, have conducted hundreds of tests to achieve mechanically reproduced. But, like many other parts of nature almost perfect, simple to sight is not so much in practice.

The heart has three great complexities to achieve emulate: the coagulation process, the rejection by the recipient’s body and energy to feed its mechanics. Now that we know roughly our hearts, let us briefly what it is an artificial one.

What is an artificial heart?

It’s a prosthesis implanted in the body, performs the same functions as a biological heart. These prostheses can be used for temporary replacements, in cases of patients on the waiting list for a donor, or in situations in which the biological heart must stop for any type of surgery. There are two types of artificial hearts, the TAH (Total Artificial Heart) and VAD (Heart Assist Device), which are divided into LVAD (LVAD) and RVAD (right ventricular assist).

A TAH is a complete replacement of the biological heart and requires the same procedure used for a heart transplant for a donor.

The VAD is a device placed near the heart to support and assist the body for some reason, you need to complement such work or recover from any situation.

That said, we proceed to do some traveling through the history of doctors and scientists, largely rejected by the companies of their time, progress in the development of an artificial heart that could finally fulfill the cherished goal of extending the people’s lives.

The pioneers in designing the first prototype

The first records of tests TAHS dating from 1937, when the Russian physician Vladimir Petrovic Demikhov tested with dogs, the placement of an implant based on a roller pump that had an engine that ran through the sternum. This event became the greatest medical achievement in the history of Russian science, since it was ahead in nearly 20 years to the first relatively successful TAH prosthesis and 30 years of historical South African heart transplant Christiaan Neethling Barnard .

Since as in Russia between the wars, nothing was subject to suspicion or mysticism. This is how Demikhov met by the pseudonym “Doctor of Horror”, as well as their testing in dogs with TAH, he held other records as somewhat creepy about thirty transplants heads and limbs in animals (usually dogs) and his famous two-headed dogs .

Until 1953 there were no known other evidence related to these implants, the year John Heysham Gibbon the doctor performed the first open heart surgery or CPB (Cardiopulmonary Bypass), installing a heart-lung machine known as “the bomb” (see image).

The source: The artificial heart image 2

Gibbon and his wife next to the machine known as the “bomb”.

Although for historians, this milestone is not usually regarded as the first artificial heart transplant, scientific interest was aroused enough for thousands of inverstigadores worldwide began to test solutions for diseases of the heart between the that was highlighted in 1957 the Research Program at the Cleveland Clinic TAH, led by Willem Kolff and Akutsu Tet.

Within this group of enthusiastic doctors said the Argentine Domingo Liotta, an Entre Rios began to experiment on TAH transplant in Lyon, France in 1958, continued during 1959 and 1960 at the National University of Cordoba (Argentina) and ended with presenting his work at the American Society for Artificial Internal Organs, held in March 1961 in Atlantic City. This work demonstrated the ability to successfully transplant TAH implants with different types of mechanisms of external energy.

Based on this research, Liotta created in 1962 the first LVAD at Baylor University College of Medicine in Houston and implements the July 19, 1963 in a patient who suffered cardiac arrest after surgery, died four days later for not have recovered from heart failure.

Three years later with Michael DeBakey, Liotta implanted the first LVAD clinical extracorporeal position a patient who survived a few days. The LVAD model known at that time as Liotta-DeBakey, was placed months later in another patient after 10 days of mechanical support was discharged. It was a matter of time before the first implant was achieved overall.

In early 1969, Domingo Liotta with Denton Cooley replace a patient’s heart to keep him alive until the arrival of the donor. He lived more than 64 hours with mechanical heart powered by pneumatic means (later replaced by a biological and died of an infection) and perhaps, some speculate that, habérselo left, could have been the foundational moment of the race for an artificial organ completely.

The original prototype of Liotta-Cooley artificial heart used in this historic operation was found, together with the incandescent lamp by Thomas Edison, among the 150 most valuable objects invented by mankind, belonging to the Smithsonian Treasures of American History in Washington DC .

Unfortunately, who should be recognized in Argentina to his 88 years as a founding father of modern medicine, its image deteriorated during his tenure as president of the National Council of Scientific and Technical Research (CONICET), which is remembered by the scientific community as most destructive and instigator of the breakup of science in Argentina during the decade of ’90, and caused the second largest scientific brain drain the country along with the persecution of the dictatorship of Juan Ongania in the ’60s .

Jarvik-7: The result of collaborative work

The source: The artificial heart image 3

Robert Jarvik and his creation, the Jarvik-7 (c) William Coupon / CORBIS.

As Domingo Liotta developed new and successful transplants, the artificial heart began to draw the attention of both the scientific community and the business it entered into the tangled world of patents war Or is believed that this invention would be the exception? The first patent for an artificial heart was recorded by American Paul Winchell in 1963, who gave it to the University of Utah, where the scientist Robert Jarvik developed the first prototype of the Jarvik-7 model that had great innovations as a material internal coating favoring the adhesion of blood and its internal walls coated with living tissue, allowing design establish a more natural flow of blood.

Robert Jarvik and had much experience in the development of dialysis machines and artificial organs, so when Pat Winchell came to their hands, many loose ends were tied on his head to design the Jarvik-7, a collaboration of dozens research that preceded it, as mentioned Winchell, Henry Heimlich and Dutchman Willem Kolff.

Jarvik became a bit of a celebrity, thanks to its progress and a strong spread of the device by the press. Unfortunately so far not managed to drive the Jarvik-7 other than through external pneumatic tubes, which added to the internal implant energy mechanism the size of a shopping cart.

In 1982, the successful transplantation of Dr. William DeVries to a patient who survived 620 days with a Jarvik-7 allowed all the front pages of the media take care of the issue, considering it a milestone in modern medicine.

These events prompted Robert Jarvik to launch his own company, Symbion Inc., which fell through because of his poor business skills.

During the ’80s, more than 90 people received the Jarvik-7, which after a few years was prohibited, and any other type of artificial implant to replace the heart due to almost no hope of survival (no more six months) that could in patients. Currently, only allowed temporary replacements artificial hearts to patients waiting for a biological donor.

The future: Bioartificial Organs and centrifugal turbines

Despite the ban on the use of artificial hearts, the Japanese doctor who specializes in artificial organs Hiroaki Harasaki, developed two important improvements that address major obstacles: a surface coating material that does not induce clotting, which significantly reduces the risk of the patient’s immune system from rejecting the organ, and an implantable power supply with a reduced heat generation so that does not damage the tissues.

Along with these advances have been known in recent years developments as a French model fully functional set up in 2008, but at a cost prohibito nearly $ 200 billion, the creation last year in Madrid the first laboratory in the world with the capacity to create organs bioartificial from adult stem cells, and even an artificial heart using centrifugal turbines to pump blood, resulting in quiet operation and replaces the beats a little buzz.

A little less than 10 months was conducted in Spain the installation of the first permanent electric pump in a damaged heart , allowing the patient to continue with their normal lives without having to be hospitalized or dragging great teams.

The future of medicine and heart transplants are at a moment of controversy related to the complexity of this “apparent” simple pumping of blood in our bodies that can not be replaced with any appliance that emulates operation and with the current regulations prohibiting the moment its replacement by unreliable equipment. Perhaps, electronics and nanotechnology could eventually contribute some of their progress to achieve the great leap scientist.

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