An artificial heart is a mechanical device that is implanted into the body to replace the biological heart. The term “artificial heart” has often inaccurately been used to describe ventricular assist devices (VADs), which are pumps that assist the heart but don’t replace it.
An artificial heart is also distinct from a cardiopulmonary bypass machine (CPB), which is an external device used to provide the functions of both the heart and lungs. CPBs are only used for a few hours at a time, most commonly during heart surgery.
CardioWest™ temporary Total Artificial Heart
The CardioWest™ temporary Total Artificial Heart (TAH-t) (SynCardia Systems, Inc.) is the world’s first and only FDA-approved Total Artificial Heart. It received FDA approval on Oct. 15, 2004, following a 10-year pivotal clinical study.
Originally designed as a permanent replacement heart, it is currently approved as a bridge to human heart transplant for patients dying because both sides of their hearts are failing (irreversible end stage biventricular failure). There have been more than 780 implants of the CardioWest artificial heart, accounting for more than 150 patient years of life on this device.
In the 10-year pivotal clinical study of the CardioWest artificial heart 79% of patients receiving the artificial heart survived to transplant (New England Journal of Medicine 2004; 351: 859-867). This is the highest bridge-to-transplant rate for any heart device in the world. See FDA Summary of Safety and Effectiveness
AbioCor® Replacement Heart
The AbioCor® Replacement Heart (Abiomed) received FDA approval under a Humanitarian Device Exemption (HDE) on Sept. 5, 2006. The AbioCor is 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. The AbioCor has been implanted 14 times. The most recent implant was May 24, 2004. See FDA Summary of Safety and Probable Benefit
A synthetic replacement for the heart remains one of the long-sought holy grails of modern medicine. The obvious benefit of a functional artificial heart would be to lower the need for heart transplants, because the demand for organs always greatly exceeds supply.
Although the heart is conceptually simple (basically a muscle that functions as a pump), it embodies subtleties that defy straightforward emulation with synthetic materials and power supplies. Consequences of these issues include severe foreign-body rejection and external batteries that limit patient mobility. These complications limited the lifespan of early human recipients to hours or days.
A heart-lung machine was used in 1953 during a successful open heart surgery. Dr. John Heysham Gibbon, the inventor of the machine, performed the operation and developed the heart-lung substitute himself.
On July 3, 1952, 41-year-old Henry Opitek suffering from shortness of breath made medical history at Harper University Hospital at Wayne State University in Michigan. The Dodrill-GMR heart machine, considered to be the first operational mechanical heart was successfully used while performing heart surgery. 
Dr. Forest Dewey Dodrill used the machine in 1952 to bypass Henry Opitek’s left ventricle for 50 minutes while he opened the patient's left atrium and worked to repair the mitral valve. In Dr. Dodrill’s post operative report he notes, “To our knowledge, this is the first instance of survival of a patient when a mechanical heart mechanism was used to take over the complete body function of maintaining the blood supply of the body while the heart was open and operated on.
The scientific interest for the development of a solution for heart disease developed in different research groups worldwide.
In 1949, a precursor to the modern artificial heart pump was built by Bill Sewell using an Erector set, assorted odds and ends, and dime store toys. The external pump successfully bypassed the heart of a dog for more than an hour.
On Dec. 12, 1957, Dr. Willem Kolff, the world’s most prolific inventor of artificial organs, implanted an artificial heart into a dog at Cleveland Clinic. The dog lived for 90 minutes.
In 1958 Domingo Liotta initiated the studies of TAH replacement at Lyon, France and in 1959-60 at the National University of Cordoba, Argentina. He presented his work at the meeting of the American Society for Artificial Internal Organs meeting held in Atlantic City in March 1961. On that meeting Dr Liotta described the implantation of three types of orthotopic (inside the pericardial sac) TAHs in dogs, each of which used a different source of external energy: an implantable electric motor, an implantable rotating pump with an external electric motor and a pneumatic pump. 
In 1967, Dr. Kolff left Cleveland Clinic to start the Division of Artificial Organs at the University of Utah and pursue his work on the artificial heart.
- In 1973, a calf named “Tony” survived for 30 days on an early Kolff heart.
- In 1975, bull “Burk” survived 90 days on the artificial heart.
- In 1976, a calf named “Abebe” lived for 184 days on the Jarvik 5 artificial heart.
- In 1981, calf “Alfred Lord Tennyson” lived for 268 days on the Jarvik 5.
Over the years, more than 200 physicians, engineers, students and faculty developed, tested and improved Dr. Kolff’s artificial heart. To help manage his many endeavors, Dr. Kolff assigned project managers. Each project was named after its manager. Graduate student Robert Jarvik was the project manager for the artificial heart, which was subsequently renamed the Jarvik 7.
In 1981, Dr. William DeVries submitted a request to the FDA to implant the Jarvik 7 into a human being. On Dec. 2, 1982, Dr. Kolff’s 35 years of dedication culminated in the first implant of the Jarvik 7 artificial heart into Dr. Barney Clark. Clark was hours from death prior to the surgery. He lived for 112 days with the artificial heart.
On Feb 11, 2009, Dr. Kolff passed away at the age of 97 in Philadelphia. See press release
In the morning of April 4 1969 Domingo Liotta and Denton A. Cooley replaced a dying man’s heart with a mechanical heart inside the chest at the Texas Heart Institute in Houston as a bridge for a transplant. The patient woke up and recovered well. After 64 hours the pneumatic powered artificial heart was removed and replaced by a donor heart. Replacing the artificial heart proved to be a bad decision, however; thirty-two hours after transplantation the patient died of what was later proved to be an acute pulmonary infection, extended to both lungs, caused by fungi, most likely caused by an immunosuppressive drugs complication. If they had left the artificial heart in place the patient may have lived longer.
The original prototype of Liotta-Cooley artificial heart used in this historic operation is prominently displayed in The Smithsonian Museum"Treasures of American History" exhibit in Washington, DC.
The eighty-fifth clinical use of an artificial heart designed for permanent implantation rather than a bridge to transplant occurred in 1982 at the University of Utah. Artificial kidney pioneer Dr. Willem Johan Kolff started the Utah artificial organs program in 1967. There, physician-engineer Dr. Clifford Kwan-Gett invented two components of an integrated pneumatic artificial heart system: a ventricle with hemispherical diaphragms that did not crush red blood cells (a problem with previous artificial hearts), and an external heart driver that inherently regulated blood flow without needing complex control systems. Independently, ventriloquist Paul Winchell designed and patented a similarly shaped ventricle, and donated the patent to the Utah program. Throughout the 1970’s and early 1980’s veterinarian Dr. Donald Olsen led a series of calf experiments that refined the artificial heart and its surgical care. During that time, as a student at the University of Utah, Dr. Robert Jarvik combined several modifications: an ovoid shape to fit inside the human chest, a more blood-compatible polyurethane developed by biomedical engineer Dr. Donald Lyman, and a fabrication method by Kwan-Gett that made the inside of the ventricles smooth and seamless to reduce dangerous stroke-causing blood clots. On December 2, 1982, Dr. William DeVries implanted the artificial heart into retired dentist Dr. Barney Bailey Clark (b. 21 January 1921), who survived 112 days with the device, dying on 23 March 1983. Bill Schroeder became the second recipient, and lived for a record 620 days.
Contrary to popular belief and erroneous articles in several periodicals, the Jarvik heart was not banned for permanent use. Since 1982 more than 350 people have received the Jarvik heart as a bridge to transplantation. http://www.jarvikheart.com/basic.asp?id=69
In the mid 1980s, artificial hearts were powered by dishwasher-sized pneumatic power sources whose lineage went back to Alpha-Laval milking machines. Moreover, two sizeable catheters had to cross the body wall to carry the pneumatic pulses to the implanted heart, greatly increasing the risk of infection. To speed development of a new generation of technologies, the National Heart, Lung, and Blood Institute opened a competition for implantable electrically powered artificial hearts. Three groups received funding: Cleveland Clinic in Cleveland, Ohio; the College of Medicine of Pennsylvania State University (Penn State Hershey Medical Center) in Hershey, Pennsylvania; and Abiomed, Inc. of Danvers, Massachusetts. Despite considerable progress, the Cleveland program was discontinued after the first five years.
The Penn State Heart is of an electromechanical design with a brushless DC motor positioned between polyurethane, sac-style right and left ventricles. As a roller screw translates rotary motion to linear motion, pusher plates alternately activate the right and left ventricles. Four Bjork-Shiley tilting disc valves ensure unidirectional blood flow. A digital electronic control system that indirectly senses arterial and left atrial pressure provides an adequate blood flow while balancing the output of the two ventricles. Energy from NiCd batteries carried in a shoulder bag or on a belt is transfered to the implanted motor wirelessly, through inductive coupling. This artificial heart has been extensively tested on artificial circulatory systems and implanted in over 50 calves, with animal survival of nearly one year.
Abiomed's AbioCor is the first fully implantable total artificial heart, which unlike previous total artificial hearts (such as the Jarvik 7) does not require wires to external devices. This replacement heart uses an electrohydraulic design with a high-speed impeller pump that pressurizes a hydraulic fluid. An energized ported valve shuttles the fluid, alternately actuating diaphragm-style left and right ventricles. Polymeric trileaflet valves ensure unidirectional blood flow with a low pressure gradient and good longevity. State-of-the art transcutaneous energy transfer eliminates the need for electric wires crossing the chest wall.
The first AbioCor to be surgically implanted in a patient was on July 3, 2001. The AbioCor is made of titanium and plastic with a weight of 2 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 4 hours. The FDA announced on September 5, 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 can not receive a heart transplant. Some limitations of the current AbioCor are that its size makes it suitable for only about 50% of the male population and its useful life is only 1 to 2 years. By combining its valved ventricles with the control technology and roller screw developed at Penn State, Abiomed has 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 5 years, had animal trials in 2005, and the company hopes to get FDA approval for human use in 2008.
In the evening of July 19 1963 E. Stanley Crawford and Domingo Liotta implanted the first clinical LVAD at the Methodist Hospital in Houston, Texas in a patient who had a cardiac arrest after surgery. The patient survived for 4 days under mechanical support but didn't recover from the complications of the cardiac arrest; finally the pump was discontinued and the patient died.
In the afternoon of April 21 1966 Michael DeBakey and Liotta implanted the first clinical LVAD in a paracorporeal position (where the external pump rests at the side of the patient) at the Methodist Hospital in Houston, in a patient experiencing cardiogenic shock after heart surgery. The patient developed neurological and pulmonary complications and died after few days of LVAD mechanical support. In October 1966 DeBakey and Liotta implanted the paracorporeal Liotta-DeBakey LVAD in a new patient who recovered well, and was discharged from hospital after 10 days of mechanical support, thus constituting the first successful use of an LVAD for postcardiotomy shock.
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 was able to function properly on its own.
With increased understanding of the heart and continuing improvements in prosthetics engineering, computer science, electronics, battery technology, and fuel cells, a practical artificial heart may become a reality.
On October 27, 2008, French professor and leading heart transplant specialist Alain F. Carpentier announced that a fully implantable artificial heart will be ready for clinical trial by 2011, and for alternative transplant in 2013. It was developed and will be manufactured by him, Biomedical firm Carmat, and venture capital firm Truffle. The prototype uses electronic sensors and is made from chemically treated animal tissues, called "biomaterials", or a “pseudo-skin” of biosynthetic, microporous materials. Another US team with prototype called 2005 MagScrew Total Artificial Heart, including Japan and South Korea researchers are racing to produce similar projects.  
See 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.
Another VAD, the Kantrowitz CardioVad, designed by Adrian Kantrowitz, MD 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.
The first heart assist device was FDA approved 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, Texas, provide continuous flow. These pumps (which may be centrifugal or axial flow) are smaller and potentially more durable and long-lasting than the current generation of total heart replacement pumps. Another major advantage of a VAD is that the patient can keep the natural heart, which can receive signals from the brain to increase and decrease the heart rate as needed. With the completely mechanical systems, the heart rate is fixed.
Several continuous flow ventricular assist devices have been approved for use in the European Union and as at August 2007 were undergoing clinical trials for FDA approval.
George B. Griffenhagen and Calvin H. Hughes. The History of the Mechanical Heart. Smithsonian Report for 1955, (Pub. 4241): 339-356, 1956.