administration. as of 2014, more than 1,250 patients have received syncardia artificial hearts. the device requires the use of the companion 2 in-hospital driver, approved by the fda in 2012, or the freedom driver system, approved in 2014, which allows some patients to return home. these drivers are large, heavy, but portable devices that generate air pulses to power the heart. the drivers also monitor blood flow for each ventricle. in 2016, syncardia filed for bankruptcy protection and was later acquired by the private equity firm versa capital management. carmat bioprosthetic heart carmat's artificial heart. on 27 october 2008, french professor and leading heart transplant specialist alain f. carpentier announced that a fully implantable artificial heart would be ready for clinical trial by 2011 and for alternative transplant in 2013. it was developed and would be manufactured by him, biomedical firm carmat sa, and venture capital firm truffle capital. the prototype used embedded electronic sensors and was made from chemically treated animal tissues, called "biomaterials", or a "pseudo-skin" of biosynthetic, microporous materials. according to a press-release by carmat dated 20 december 2013, the first implantation of its artificial heart in a 75-year-old patient was performed on 18 december 2013 by the georges pompidou european hospital team in paris (france). the patient died 75 days after the operation. in carmat's design, two chambers are each divided by a membrane that holds hydraulic fluid on one side. a motorized pump moves hydraulic fluid in and out of the chambers, and that fluid causes the membrane to move; blood flows through the other side of each membrane. the blood-facing side of the membrane is made of tissue obtained from a sac that surrounds a cow's heart, to make the device more biocompatible. the carmat device also uses valves made from cow heart tissue and has sensors to detect increased pressure within the device. that information is sent to an internal control system that can adjust the flow rate in response to increased demand, such as when a patient is exercising. this distinguishes it from previous designs that maintain a constant flow rate. the carmat device, unlike previous designs, is meant to be used in cases of terminal heart failure, instead of being used as a bridge device while the patient awaits a transplant. at 900 grams it weighs nearly three times the typical heart and is targeted primarily towards obese men. it also requires the patient to carry around an additional li-ion battery. the projected lifetime of the artificial heart is around 5 years (230 million beats). in 2016, trials for the carmat "fully artificial heart" were banned by the national agency for security and medicine in europe after short survival rates were confirmed. the ban was lifted in may 2017. at that time, a european report stated that celyad's c-cure cell therapy for ischemic heart failure "could only help a subpopulation of phase iii study participants, and carmat will hope that its artificial heart will be able to treat a higher proportion of heart failure patients". the carmat artificial heart was approved for sale in the european union, receiving a ce marking on december 22, 2020. its stock price increased over a third upon the announcement of the news. total artificial heart pump the u.s. army artificial heart pump was a compact, air-powered unit developed by kenneth woodward at harry diamond laboratories in the early to mid-1960s. the army's heart pump was partially made of plexiglass, and consisted of two valves, a chamber, and a suction flapper. the pump operated without any moving parts under the principle of fluid amplification – providing a pulsating air pressure source resembling a heartbeat. polvad since 1991, the foundation for cardiac surgery development (frk) in zabrze, poland, has been working on developing an artificial heart. nowadays, the polish system for heart support polcas consists of the artificial ventricle polvad-mev and the three controllers polpdu-401, polpdu-402 and polpdu-501. presented devices are designed to handle only one patient. the control units of the 401 and 402 series may be used only in hospital due to its big size, method of control and type of power supply. the control unit of 501 series is the latest product of frk. due to its much smaller size and weight, it is significantly more mobile solution. for this reason, it can be also used during supervised treatment conducted outside the hospital. phoenix-7 in june 1996, a 46-year-old man received a total artificial heart implantation done by jeng wei at cheng-hsin general hospital in taiwan. this technologically advanced pneumatic phoenix-7 total artificial heart was manufactured by taiwanese dentist kelvin k. cheng, chinese physician t. m. kao, and colleagues at the taiwan tah research center in tainan, taiwan. with this experimental artificial heart, the patient's bp was maintained at 90–100/40–55 mmhg and cardiac output at 4.2–5.8 l/min. the patient then received the world's first successful combined heart and kidney transplantation after bridging with a total artificial heart. abiomed hearts the first abiocor to be surgically implanted in a patient was on 3 july 2001. the abiocor is made of titanium and plastic with a weight of 0.9 kg (two pounds), and its internal battery can be recharged with a transduction device that sends power through the skin. the internal battery lasts for half an hour, and a wearable external battery pack lasts for four hours. the fda announced on 5 september 2006, that the abiocor could be implanted for humanitarian uses after the device had been tested on 15 patients. it is intended for critically ill patients who cannot receive a heart transplant. some limitations of the current abiocor are that its size makes it suitable for less than 50% of the female population and only about 50% of the male population, and its useful life is only 1–2 years. by combining its valved ventricles with the control technology and roller screw developed at penn state, abiomed designed a smaller, more stable heart, the abiocor ii. this pump, which should be implantable in most men and 50% of women with a life span of up to five years, had animal trials in 2005, and the company hoped to get fda approval for human use in 2008. after a great deal of experimentation, abiomed has abandoned development of total official hearts as of 2015. abiomed as of 2019 only markets heart pumps, "intended to help pump blood in patients who need short-term support (up to 6 days)", which are not total artificial hearts. frazier-cohn on 12 march 2011, an experimental artificial heart was implanted in 55-year-old craig lewis at the texas heart institute in houston by o. h. frazier and william cohn. the device is a combination of two modified heartmate ii pumps that is currently undergoing bovine trials. frazier and cohn are on the board of the bivacor company that develops an artificial heart. bivacor has been tested as a replacement for a heart in a sheep. so far, only one person has benefited from frazier and cohn's artificial heart. craig lewis had amyloidosis in 2011 and sought treatment. after obtaining permission from his family, frazier and cohn replaced his heart with their device. lewis survived for another 5 weeks after the operation; he eventually died from liver and kidney failure due to his amyloidosis, after which his family asked that his artificial heart be unplugged. soft total artificial heart, developed in the functional material laboratory at eth zürich soft artificial heart on 10 july 2017, nicholas cohrs and colleagues presented a new concept of a soft total artificial heart in the journal of artificial organs. the heart was developed in the functionals materials laboratory at eth zurich. (cohrs was listed as a doctoral student in a group led by professor wendelin stark at eth zurich.) the soft artificial heart (sah) is a silicone monoblock fabricated with the help of 3d printing technology. it weighs 390g, has a volume of 679 cm3, and is operated through pressurized air. "our goal is to develop an artificial heart that is roughly the same size as the patient's own one and which imitates the human heart as closely as possible in form and function", cohrs said in an interview. the sah fundamentally moves and works like a natural heart, but the prototype only performed for 3000 beats (about 30 to 50 minutes at an average heart rate) in a hybrid mock circulation machine before the silicone membrane (2.3 mm thick) between the left ventricle and the air expansion chamber ruptured. the working life of a more recent cohrs prototype (using various polymers instead of silicone) was still limited, according to reports in early 2018, with that model providing a useful life of 1 million heartbeats, roughly ten days in a human body. at the time, cohrs and his team were experimenting with cad software and 3d printing, striving to develop a model that would last up to 15 years. "we cannot really predict when we could have a final working heart which fulfills all requirements and is ready for implantation. this usually takes years", said cohrs. others a centrifugal pump or an axial-flow pump can be used as an artificial heart, resulting in the patient being alive without a pulse. other pulse-less artificial heart designs include the heartmate ii from thoratec, which uses an archimedes screw; and an experimental artificial heart designed by bud frazier and billy cohn, using turbines spinning at 8,000 to 12,000 rpm. a centrifugal artificial heart which alternately pumps the pulmonary circulation and the systemic circulation, causing a pulse, has been described. researchers have constructed a heart out of foam. the heart is made out of flexible silicone and works with an external pump to push air and fluids through the heart. it currently cannot be implanted into humans, but it is a promising start for artificial hearts. hybrid assistive devices main article: ventricular assist device patients who have some remaining heart function but who can no longer live normally may be candidates for ventricular assist devices (vad), which do not replace the human heart but complement it by taking up much of the function. the first left ventricular assist device (lvad) system was created by domingo liotta at baylor college of medicine in houston in 1962. another vad, the kantrowitz cardiovad, designed by adrian kantrowitz, boosts the native heart by taking up over 50% of its function. additionally, the vad can help patients on the wait list for a heart transplant. in a young person, this device could delay the need for a transplant by 10–15 years, or even allow the heart to recover, in which case the vad can be removed. the artificial heart is powered by a battery that needs to be changed several times while still working. the first heart assist device was approved by the fda in 1994, and two more received approval in 1998. while the original assist devices emulated the pulsating heart, newer versions, such as the heartmate ii, developed by the texas heart institute of houston, provide continuous flow. these pumps (which may be centrifugal or axial flow) are smaller and potentially more durable and last longer than the current generation of total heart replacement pumps. another major advantage of a vad is that the patient keeps the natural heart, which may still function for temporary back-up support if the mechanical pump were to stop. this may provide enough support to keep the patient alive until a solution to the problem is implemented. in august 2006, an artificial heart was implanted into a 15-year-old girl at the stollery children's hospital in edmonton, alberta. it was intended to act as a temporary fixture until a donor heart could be found. instead, the artificial heart (called a berlin heart) allowed for natural processes to occur and her heart healed on its own. after 146 days, the berlin heart was removed, and the girl's heart functioned properly on its own. on 16 december 2011 the berlin heart gained u.s. fda approval. the device has since been successfully implanted in several children including a 4-year-old honduran girl at children's hospital boston. several continuous-flow ventricular assist devices have been approved for use in the european union, and, as of august 2007, were undergoing clinical trials for fda approval. in 2012, craig lewis, a 55-year-old texan, presented at the