We all know that we need a heart to live, but the human heart is quite susceptible to damage and diseases that can only be prevented up to a point. A heart attack occurs when oxygen-rich blood is blocked, and so is not pumped to a part of heart muscle. We can take limited measures to prevent such an occurrence from happening, such as by eating healthy food, but we cannot reduce the possibility of occurrence to 0%. If blood flow isn’t restored early enough, the deprived section of heart muscle will begin to die. When I was a child, I learnt that we humans need two things to live: a heart, and a brain. However, with the current state of our medical technology, do we actually need a heart anymore to be a living human?
A Heartfelt History
The Early Years
Since the human heart functions so repetitively – its job is essentially to pump blood – doctors thought they could mimic such activity. The first artificial pump was created by French surgeon Alexis Carrel and American aviator Charles Lindberg, in 1935. This perfusion pump worked outside the human body, and it functioned to keep unattached organs alive by circulating blood. The first model for a total artificial heart (TAH) was created by William Glenn and William Sewell in the early 1950′s, but it seems to have been more of a theoretical milestone than a practical solution.
The first TAH surgery was conducted on a dog, by a Dutch physician, Willem Kolff, and Japanese thoracic surgeon, Tetsuzo Akutsu - both of whom died recently. The surgery took place in a clinic in the U.S., in 1957, but the dog lived for only an hour and a half afterwards. But this made an impression on the National Institutes of Health (NIH), who would establish the Artificial Heart Program in 1964, with the goal of putting a man-made organ into a human by the end of the decade.
In 1966, American cardiac surgeon Adrian Kantrowitz performed the first permanent partial artificial heart (PAH) device, which assisted with the left ventricle. This was significant, because the majority of severe heart diseases are caused by failure in the left ventricle. It was after this procedure when the South African cardiac surgeon Christiian Barnard performed the first human-to-human heart transplant, which was a major accomplishment for medicine.
Soon after, the first implantation of a TAH in a human was complete in 1969. The Argentinian artificial-heart technician, Domingo Liotta, had created an artificial heart which the American surgeon Denton Cooley would use on the 47-year-old Haskell Karp, at St. Luke’s hospital. The Daily Mail had an interesting piece on this last year, describing the controversial lengths Cooley went to keep his previous colleague out of the honor of having the artificial-heart named after him as well. Indeed, the device, which now remains in the Smithsonian Institute, is called the “Liotta-Cooley Artificial Heart.” As the Daily Mail reports:
The device caused a famous long-running feud between the two leading heart surgeons of the time Dr Michael E DeBakey and Dr Cooley.
The duo pioneered operations in the 1950s at Baylor College of Medicine and Methodist Hospital in Houston. However, Dr Cooley moved to St Luke’s Hospital in 1960 and in 1969 he took an artificial heart from his former partner’s lab without approval.
He then implanted it in Mr Karp in a medical first, with the help of Dr DeBakey’s artificial-heart technician, Dr Domingo Liotta. Dr DeBakey had never sought approval to use the device in a patient, as it had only been partially tested on calves. According to the New York Times the surgeon was furious when he heard about the implant calling it ‘unethical’ and ‘a childish act.’
‘He wanted to be able to say he was the first one to use an artificial heart in a patient,’ Dr DeBakey said.
Dr Cooley defended the implant as a desperate act to save a life, which unfortunately failed. He added that he was the most experienced heart surgeon of the time.
Dr Cooley attempted to arrange a meeting with Dr DeBakey for decades but was repeatedly rebuffed. They finally reconciled in 2007 when DeBakey was 99 and Cooley was 87. Dr DeBakey died a year later.
American biomedical engineer Robert Jarvik and ventriloquist-turned-inventor Paul Winchell are both technically credited with the “Jarvik-7 total artificial heart,” which was invented in 1982. The device was a major success story in artificial heart technology, but there is a lot of debate over Winchell and Jarvik’s involvement in its creation.
Paul Winchell, and many other sources, have continuously claimed that Jarvik-7 used parts that Winchell had patented. JarvikHeart.com says “Paul Winchell’s claims have been erroneously repeated by respected publications such as the Washington Post, which failed to fact-check the information. [. . .] [In fact, a] search of “Paul Winchell” and “artificial heart” on Google gives almost 2,000 articles, many of which erroneously repeat Paul Winchell’s false claims as if they were fact. [. . .] [However, the] Jarvik-7 did not use any of the mechanisms patented by Paul Winchell, and was an entirely separate development.”
The device went through many changes, and its named evolved with the modifications. It was first renamed the “Symbion total artificial heart,” and then the “CardioWest total artificial heart.” The latest version we see today is called the “SynCardia temporary total artificial heart.” The word “temporary” reflects the fact that today’s artificial heart technology, such as artificial pacemakers, are now surgically implanted in order to replace the heart only temporarily. They are essentially there to bridge the gap between the time your heart files and you receive a new one.
The first Jarvik-7 implant was conducted in 1982, by American carthiothoracic surgeon William DeVries. The recipient was a patient named “Barney Clark,” who was a suitable candidate because he was medically unfit for heart transplant. The procedure gave him 112 more days to live. By the late 80′s the Jarvik-7 had extended over 70 people’s lives, including the second-ever implant recipient, William Schroeder, who survived for 620 days after his surgery in 1985.
The Golden Age of Heart Technology
Assisting, not Replacing
There has been a lot of progress with artificial hearts, but as the technology advanced, a new distinction emerged: A Ventricular Assist Device (VAD). Wikipedia’s definition is helpful:
VADs need to be clearly distinguished from artificial hearts, which are designed to completely take over cardiac function and generally require the removal of the patient’s heart. VADs are designed to assist either the right (RVAD) or left (LVAD) ventricle, or both at once (BiVAD). Which of these types is used depends primarily on the underlying heart disease and the pulmonary arterial resistance that determines the load on the right ventricle.
One such VAD is the Berlin Heart, which was approved for usage in the U.S. in 1994, and designed specifically for children. Flash forward to 2006, when 15 year old Canadian Melissa Mills made history. After a sudden illness resulted in the rapid deterioration of her heart, she was given the Berlin Heart in order to keep her alive until she could receive a new heart.
Miraculously, a few months after the operation, Melissa’s condition improved, and with the time spent resting, her heart muscle had regained a lot of its strength. The happy end to the story is that, after 146 days on the Berlin Heart, they were able to give her her own heart back. There have fortunately been many more success stories with the Berlin Heart.
And the technology is getting even better.
Beating Hearts and Broken Hearts
Previous artificial hearts were associated with problems such as gradually wearing out or breaking down, as well as causing clots or infections. However, researchers Billy Cohn and Bud Frazier at the Texas Heart Institute have developed a machine that uses whirling rotors instead of the pumping action. Essentially, they have gotten rid of the idea of a heart with a pulse. In fact, the 8-month-old calf that received the device is, as Cohn said, “by every metric we have to analyze patients [. . .] not living. But here you can see she’s a vigorous, happy, playful calf.”
After practicing the procedure on 38 calves, the doctors turned their sites onto a human patient. As NPR reports:
Craig Lewis, a 55-year-old who was dying from amyloidosis, which causes a buildup of abnormal proteins. The proteins clog the organs so much that they stop working. In Lewis’ case, his heart became so damaged, doctors said he had about 12 hours left to live. His wife, Linda, said they should try the artificial heart.
[. . .] After the implant, Craig Lewis woke up and recovered somewhat. He could speak and sit up in a chair. But then he began to fade as the disease attacked his liver and kidneys. Craig Lewis lived for more than a month with the pulseless heart. He died in April, due to the underlying disease. His doctors say the pumps themselves worked flawlessly.
“We knew if it wasn’t a success for Craig, if they could get data that would help them, if it helps the next person, then you did good,” Linda Lewis says.[. . .] In order to bring a continuous-flow artificial heart to the market, the doctors will have to decide on a final design, find a manufacturer and get FDA approval. Although there’s more work to be done, Frazier says he’s confident the pulseless approach will win out in the end. “These pumps don’t wear out,” he says. “We haven’t pumped one to failure to date.”
The information above shows that we have technology that may be able to replace or complement a damaged or failed heart, but I’m happy to say that the science is getting even better. A new study, released on Valentine’s Day on the online version of The Lancet, used a new procedure developed by Cuban-born Eduardo Marbán, director of the Cedars-Sinai Heart Institute. The procedure involves treating people with stem cells – taken from the patients themselves – to reduce the size of scarring left by a heart attack. Patients also experienced an increase in healthy heart muscle after the treatment. The following video is a fantastic look at the study from the perspective of a patient who is a video-journalist:
The study, which will be published in the print version of the Lancet soon, had promising results. A year after the treatment, MRI scans showed that scar size reduced from 24% to 12%, as opposed to the eight patients in the control group, which showed no reduction. More research must be done, as there were only 25 patients involved in the study, but the study has been well received at a major presentation at CIRM. Marbán said that heart attack patients could see this treatment in as early as four years if results continue to be so positive.
The contributions of people from all over the world can be seen in the history of artificial heart technology. They are contributing not only to the technology of medicine, but to the philosophy of life. What it means to be human is a notion that science now challenges with every new innovation; and it appears that we actually do not need a pulse to be alive.
Perhaps the beating heart will be a relic of mankind in this early era of our technological revolution. All we know for sure is that science is going to take us to wherever we are going.