Artificial Hearts Without Heartbeats

The interesting question regarding the removal of the human heartbeat is the impact it will have on other bodily systems. Will it extend life by reducing stress on, for example, vulnerable blood vessels in the brain, or will it shorten life by also eliminating the beneficial response to that stress? Researchers are making progress in artificial hearts, so this question will likely be answered at some point over the next few decades: "The search for the perfect artificial heart seems never-ending. After decades of trial and error, surgeons remain stymied in their quest for a machine that does not wear out, break down or cause clots and infections. But Dr. Billy Cohn and Dr. Bud Frazier at the Texas Heart Institute say they have developed a machine that could avoid all that with simple whirling rotors - which means people may soon get a heart that has no beat. Inside the institute's animal research laboratory is an 8-month-old calf with a soft brown coat named Abigail. Cohn and Frazier removed Abigail's heart and replaced it with two centrifugal pumps. ... If you listened to her chest with a stethoscope, you wouldn't hear a heartbeat. If you examined her arteries, there's no pulse. If you hooked her up to an EKG, she'd be flat-lined. ... The pumps spin Abigail's blood and move it through her body. ... The doctors say the continuous-flow pump should last longer than other artificial hearts and cause fewer problems. That's because each side has just one moving part: the constantly whirling rotor. But Cohn says they will still have to convince the world that you don't need a pulse to live. ... We look at all the animals, insects, fish, reptiles and certainly all mammals, and see a pulsatile circulation. And so all the early research and all the early efforts were directed at making pulsatile pumps. ... However, the only reason blood must be pumped rhythmically instead of continuously is the heart tissue itself. ... The pulsatility of the flow is essential for the heart, because it can only get nourishment in between heartbeats. If you remove that from the system, none of the other organs seem to care much."

Link: http://www.npr.org/2011/06/13/137029208/heart-with-no-beat-offers-hope-of-new-lease-on-life

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