A pulse no longer necessary for life

by Deborah Braconnier report
This X-ray image shows the dual turbinelike blood pumps that replaced patient's heart. Image: Texas Heart Institute

(PhysOrg.com) -- While most people connect a pulse and a heartbeat to life, Dr. Billy Cohn and Dr. Bud Frazier from the Texas Heart Institute have found a way to keep the blood circulating and extend the life of patients while taking away their pulse.

Researchers have spent years trying to perfect an artificial heart that does not break down, wear out, or cause and infections. However, Cohn and Frazier have developed an artificial heart, of sorts, that seems to do the trick. The only catch is it isn’t a heart. There is no . There is no pulse. If a patient had one of their new hearts, the patient would appear dead. Attaching an EKG would return a flat-line.

The new device uses technology that has been used to aid failing hearts since the 1980s. A ventricular assist device, or VAD, is a circulatory device designed to assist either the right or left ventricle of the heart. The VADs have a rotor of blades that circulate and push the blood forward in a continuous flow.

While VADs are typically used to help one section of the heart, Cohn and Frazier hooked two of these VADs together so they would essentially work as both sides of the heart. They began working on calves and currently have an 8-month-old calf named Abigail who has no heart. Her heart was removed and in its place the doctors inserted their new pump device. Abigail is a healthy and active young calf, however, according to any medical cardiac tests, she would appear dead.

Cohn and Frazier, after testing on 38 calves, wanted to take this new pump one step further and test it on a human patient. This is where Craig Lewis, a 55-year-old man who was dying from amyloidosis comes in. His heart had become so damaged from the disease that doctors had only given him about 12 hours to live. Lewis and his wife agreed to let the doctors try the new pump to try and extend his life, if even for a short time. The doctors inserted the new pumps and Lewis did recover and had another month of life before the disease took other organs. His new heart however worked flawlessly.

Cohn and Frazier still have much work to do before the new will be available. A final design must be determined, a manufacturer must be found and they must apply for FDA approval. Results show amazing promise and may be the new future in artificial hearts.

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Jaeherys
5 / 5 (2) Jun 15, 2011
Wow that's just crazy! All this time and no one thought to do this. People have spent so much time trying to replicate the heart and completely ignored a replacement that imitates its functionality. In retrospec it seems so obvious, but isn't that always the case!
FrankHerbert
2.3 / 5 (9) Jun 15, 2011
Well that's just the thing, it doesn't imitate the heart's functionality. IIRC earlier implantable artificial hearts produced a pulse in an attempt to more closely imitate a natural heart.

Nature rarely uses the best design. Intelligent my ass ;-)
DarwiN100
not rated yet Jun 15, 2011
Nice. But what about the flow rate. Our blood does not circulate with a constant speed, so I dont see how one could go running a marathon with this device and with a constant flow..
Other modern artificial hearths have already developed ways to address this, but there is no mention of this problem in this article..
Vendicar_Decarian
1 / 5 (1) Jun 15, 2011
I doubt if Craig Lewis was too concerned about the subtle changes in the flow rate associated with exercise.
DarwiN100
not rated yet Jun 15, 2011
Vendicar: No, no, I am obviously not talking about mr. Lewis... I am just wondering, because I also just googled around for more info and these two doctors seem to suggest that this technology will prevail and all other designs will go obsolete..
Than this flow rate becomes a real issue, so I am just curious and interested to know.
Ramael
5 / 5 (2) Jun 15, 2011
Well that's just the thing, it doesn't imitate the heart's functionality. IIRC earlier implantable artificial hearts produced a pulse in an attempt to more closely imitate a natural heart.

Nature rarely uses the best design. Intelligent my ass ;-)


Haha, its true. We are a product of evolution, we are a product of mistakes. :P
Bob_Kob
not rated yet Jun 15, 2011
Well I suppose even without variable bloodflow this is better than death! Eventually it should be possible to intercept the nerve that controls heart rate to control the pump.
gwrede
not rated yet Jun 15, 2011
The blood flow is constant compared to a pounding heart. Therefore, no pulse.

But, it has to be adjusted for different activities. Sleeping, washing the dishes, walking, climbing stairs, and running, all need a different blood flow speed. A real heart replacement needs a micro processor to keep the flow speed right for the occasion.

That was implicit in the article. Unfortunately the writer focused too much on the "Look Ma, no pulse" aspect.
chthonic
5 / 5 (1) Jun 15, 2011
FrankHerbert:
Nature rarely uses the best design. Intelligent my ass ;-)
Right, for really intelligent design go to Ix or Tleilax, or, if you're looking to save money, Richese. :-)
Neurons_At_Work
not rated yet Jun 15, 2011
Does anyone remember the movie 'Threshold' which stars Donald Sutherland and Jeff Goldblum as doctors/inventors of an internally powered turbine artificial heart? It was released in the US in 1983 and the plot line parallels this discovery in many uncanny ways, from the near identical device design, to testing on calves, and also the ethical dilemma of having no pulse. Amazing sometimes how life imitates art.
aroc91
not rated yet Jun 15, 2011
Does anyone remember the movie 'Threshold'...?


Never seen it. Based on this line alone-

ethical dilemma of having no pulse


I don't want to see it, because frankly, that's just stupid. How is not having a pulse an ethical dilemma?
jscroft
not rated yet Jun 15, 2011
The reciprocating engine always was kind of a dumb idea.
mrwolfe
not rated yet Jun 16, 2011
Wow that's just crazy! All this time and no one thought to do this. People have spent so much time trying to replicate the heart and completely ignored a replacement that imitates its functionality. In retrospec it seems so obvious, but isn't that always the case!


Actually, the idea isn't that new. A team in Australia had a prototype that uses a similar idea working a decade ago.
Eric_B
not rated yet Jun 16, 2011
this would make the recipient a better sniper.

heartbeat is one factor that causes involuntary movements.
orgon
not rated yet Jun 16, 2011
All this time and no one thought to do this.
Of course he though, but not all turbine design are worth to consider. The blood isn't water and the pump action shouldn't destroy the blood cells.
dsl5000
not rated yet Jun 17, 2011
if this becomes main stream i hope they have a tag to identify people with turbines as hearts. A defibrillator and CPR would do nothing (design looks rigid, chest compressions would be rendered in-effective?).

Also i wonder what the effects would be on the aorta, considering it will have a constant pressure instead of the standard "lub-dub" which fluctuates between high and low pressure. What's the consequence of eliminating diastole?
jscroft
not rated yet Jun 17, 2011
What's the consequence of eliminating diastole?


I'm no doctor, but it seems to me that a steady pressure would eliminate a lot of wear and tear associated with repetitive beating.
orgon
not rated yet Jun 18, 2011
I'm no doctor, but it seems to me that a steady pressure would eliminate a lot of wear and tear associated with repetitive beating.

But it could make the blood flow more prone to clogging.
FroShow
not rated yet Jun 18, 2011
I was thinking the same as orgon.
I imagine that some biological processes might rely on the pulsating blood flow.
Nonetheless, any blood flow's better than none.
hush1
not rated yet Jun 18, 2011
Doctors? Without stethoscopes?
Of course, there will always be purpose for stethoscopes. Just not the original purpose. One less subject in medical school.