Artificial heart

An artificial heart is a mechanical device designed to be surgically implanted in a human patient as a temporary replacement for a biological heart. Artificial hearts are powered by batteries that allow them to mimic the functions of real hearts by pumping blood throughout the body. As of the early twenty-first century, artificial hearts are not designed for long-term use. Instead, they are intended to keep patients alive for months while they await a transplant using a donated heart.

Artificial hearts were developed primarily in the United States in the latter half of the twentieth century. The first working artificial heart was developed by Argentinian doctor Domingo Liotta and transplanted into a patient in Texas in 1969. Dutch doctor Willem Johan Kolff and his research team, which notably included Dr. Robert Jarvik, improved the functionality of artificial hearts at the University of Utah into the 1970s and 1980s.

Their work resulted in the Jarvik 7 artificial heart, which went on to become the most commonly used such device for temporary heart replacements. The Jarvik 7 was later renamed the SynCardia temporary total artificial heart, the signature product of the American medical company SynCardia Systems, LLC. In the early twenty-first century, this was the only such product approved for patient implantation by the Food and Drug Administration (FDA) and international medical community.

Background

Artificial hearts temporarily replace the ventricles, or the two lower chambers, of the heart. Ventricles are responsible for the heart's pumping. Artificial hearts are generally implanted in patients who have end-stage heart failure and need heart transplants to survive. Heart failure occurs when the heart cannot pump enough to satisfy the body's requirements. Treatment for the condition may help, but individuals with end-stage heart failure usually die if they do not receive heart transplants. Because waiting lists for donor hearts are typically long, artificial hearts keep patients alive for months while they wait for an organ to become available. In the early twenty-first century, artificial hearts were not capable of replacing the human heart permanently.

Artificial hearts are generally made of metal and plastic. The process of implanting them in the human body is complex and involves risks to patients if not performed correctly. Successfully implanted artificial hearts are attached to the organ's upper chambers, or atria, and function as mechanical substitutes for ventricles.

The SynCardia total artificial heart, manufactured by the American company SynCardia Systems, was the most popularly used artificial heart in the early twenty-first century. The heart device is first attached to a patient's atria. Pneumatic tubes connected to the device run to the patient's waist and exit from the abdomen. The tubes are connected to an external portable battery pack that forces compressed air though the tubes and into the artificial heart. These powerful airstreams allow the heart to pump blood through the body just as a healthy natural heart would.

Another type of artificial heart that received limited use in the early twenty-first century was the AbioCor total artificial heart, created by the medical devices company Abiomed and first implanted in a patient in 2001. Unlike the SynCardia heart, the AbioCor artificial heart was contained entirely within patients' bodies. The battery packs that powered the heart were installed in patients' abdomens during surgery. The batteries were recharged with an external energy-transfer device. The AbioCor heart had mostly fallen out of use by the 2010s.

Overview

The development of artificial hearts began chiefly in the United States about the middle of the twentieth century. Dutch doctor Willem Johan Kolff had experimented with creating an artificial kidney in the 1930s in the Netherlands. In 1947, he started researching ideas for a heart-lung machine and artificial heart. Kolff and his family relocated to the United States in 1950, where he began working as a research assistant at the Cleveland Clinic in Ohio.

Kolff and Dr. Tetsuzo Akutsu produced a crude version of an artificial heart in 1957. It kept a dog alive for about ninety minutes. Ten years later, Kolff left the Cleveland Clinic to work for the Division of Artificial Organs at the University of Utah. With a team of assistants, Kolff continued his research into designing an effective artificial heart. Meanwhile, at the Texas Heart Institute in 1969, Dr. Denton Cooley implanted the first artificial heart, designed by Dr. Domingo Liotta, into a human patient. The heart kept the patient alive for about sixty-four hours, but the patient died the day after receiving a donor heart.

In the early 1970s, Kolff brought several more researchers onto his team at the University of Utah to perfect the design of a viable artificial heart. The researchers included veterinarian Don Olsen, medical engineer Robert Jarvik, and surgeon William DeVries. Each would use his expertise for a different part of the research and experimentation. Jarvik was to design several types of artificial hearts, Olsen would oversee the devices implanted in animal subjects, and DeVries would transition the team from animal to human subjects.

In 1982, after years of animal experimentation with Jarvik's hearts, DeVries implanted the Jarvik 7 total artificial heart into Dr. Barney Clark, a dentist. Clark died almost four months later. The Jarvik 7 heart was occasionally implanted in patients throughout the United States over the next decade, with mostly successful results. Several doctors and medical engineers founded the company SynCardia Systems, LLC in 2001 in Tucson, Arizona, to sell the Jarvik 7 heart, which was renamed the CardioWest artificial heart. In 2004, the FDA approved the CardioWest for use as a temporary replacement heart for patients awaiting donor hearts.

Into the 2010s, SynCardia Systems touted its artificial heart, the SynCardia temporary total artificial heart, as the only such product in the world that had been approved by the FDA, Health Canada, and European Conformity, the standards governing products sold in European markets. The company also advertised its artificial heart as weighing less than the hearts of its various competitors. SynCardia's hearts, which weighted less than half the weight of a real human heart, could be fitted into patients with smaller frames, thus making them available for more people. The SynCardia heart had been implanted in more than 1,600 patients around the world by the mid-2010s.

Bibliography

"AbioCor Implantable." Texas Heart Institute, www.texasheart.org/Research/Devices/abiocor.cfm. Accessed 9 Mar. 2017.

"Artificial Heart Timeline." SynCardia Systems, LLC, www.syncardia.com/resources/artificial-heart-timeline.html. Accessed 9 Mar. 2017.

Bonsor, Kevin. "How Artificial Hearts Work." How Stuff Works, science.howstuffworks.com/innovation/everyday-innovations/artificial-heart.htm. Accessed 9 Mar. 2017.

"A Brief History of Heart Transplantation." Columbia University Department of Surgery, columbiasurgery.org/heart-transplant/brief-history-heart-transplantation. Accessed 9 Mar. 2017.

"Liotta-Cooley Artificial Heart." National Museum of American History, americanhistory.si.edu/collections/search/object/nmah‗688682. Accessed 9 Mar. 2017.

"Most Important Inventions of the 21st Century: in Pictures." Telegraph, 19 Jan. 2017, www.telegraph.co.uk/technology/2016/03/09/most-important-inventions-of-the-21st-century-in-pictures/abiocor-artificial-heart/. Accessed 9 Mar. 2017.

"7 Things about Artificial Hearts That You Should Know." SynCardia Systems, LLC, 12 Sept. 2014, www.syncardia.com/2014-press-releases/7-things-about-artificial-hearts-that-you-should-know.html. Accessed 9 Mar. 2017.

"Total Artificial Heart Facts." SynCardia Systems, LLC, www.syncardia.com/total-facts/total-facts.html. Accessed 9 Mar. 2017.

"What Is a Total Artificial Heart?" National Heart, Lung, and Blood Institute, www.nhlbi.nih.gov/health/health-topics/topics/tah. Accessed 9 Mar. 2017.