For most people, the mention of ‘heart’ brings to mind the symbol of love – the famed and much loved cherry red symbol that bombards you on Valentine’s Day. This symbol of the heart is reportedly a representation of a 6th century B.C. aphrodisiac found in Africa.
In real life, the heart looks quite a bit different from its symbolic representation. Weighing in at about 5 ounces, the human heart beats roughly once per second – that’s roughly 2.5 billion times in a life time. On an average, it pumps 74 liters of blood every hour through the adult body.
Working constantly from the minute we take human form, with many additional stresses loaded onto it during our adult life, it’s no wonder the heart is usually the first of our organs to give out. Since human beings are not very good at changing their lifestyle to sustain healthy bodies or healthy hearts – doctors have been trying for more than four decades to develop an artificial device that can take over the pumping function of the heart. The search has been to develop a machine that does not wear out, break down or cause clots and infections.
The Artificial Heart
An artificial heart is a mechanical device that replaces the heart. Artificial hearts are typically used as a temporary device that works in your body till a real heart transplant is possible; or to permanently replace the heart in case transplantation is impossible. The first artificial heart was the Jarvik-7, designed by Robert Jarvik.
The first time an artificial heart was successfully transplanted into a human was in 1969 in Houston. This was to act as a bridge for a transplant. The patient died later due to complications of an unrelated acute pulmonary infection following the heart transplant. In 2004, the FDA in the USA approved the SynCardia temporary Total Artificial Heart. Originally designed as a permanent replacement heart, it is currently approved as a bridge to human heart transplant. There have been more than 900 implants of the Total Artificial Heart, accounting for more than 210 patient years of life on this device.
Another device – the AbioCor has also been recently approved for use in severe biventricular end-stage heart disease patients, who are not eligible for heart transplant and have no other viable treatment options. As of April 2011, 14 patients had been implanted with the AbioCor, with one patient living for 512 days with the AbioCor. This device is fully implantable, meaning that there are no wires or tubes penetrating the skin, which mean there are less chances of infection.
Heart with No Beat Offers New Lease on Life
Of late, radical advances are being made, with Dr. Billy Cohn and Dr. Bud Frazier of the Texas Heart Institute announcing that they have developed a machine that can function as a heart. The device is a set of 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 listen to her chest with a stethoscope, you wouldn’t hear a heartbeat,” says Cohn. “If you examined her arteries, there’s no pulse. If you hooked her up to an EKG, she’d be flat-lined.” But she is a fully active, healthy calf!
They took two medical implants known as’ ventricular assist devices’ and hooked them together. A ventricular assist device has a screw-like rotor of blades, which pushes the blood forward in a continuous flow. 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.
In Queensland’s University of Technology, a new counter-flow heart pump is being developed which is based on a double-output centrifugal model – it pushes the blood in such a way that correct flow happens through both sides of the heart. This means that the left and right sides of the heart are supported at the same time – much like a real heart! Lead researcher Associate Professor Andy Tan says “what’s so groundbreaking is that it is the first device to combine the function of two pumps into one unit.”
Finding a technology that can serve as a replacement heart is crucial – especially because the number of people suffering from heart failure is increasing and the numbers of heart donors are not rising. So the only way to reduce the number of deaths is to find another solution.
The stages of final design and patenting are yet to be negotiated before these devices reach the chest cavities of heart patients. The world will be watching to see how effective these devices are as a solution to replacing the human heart. And even if it does, will this mean that the person having it will be semi-robot? Will they lose out on feelings and emotions? All that remains to be seen, but we can be sure of one thing. If it does work, many artificial heart recipients will be thanking their surgeons, ‘from the bottom of their hearts’!
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