|HISTORY OF MEDICINE
|Year : 2007 | Volume
| Issue : 2 | Page : 70-76
The artificial heart
Director, Non-invasive Cardiac Laboratory, Cardiology and Cardiovascular Surgery Department, Hamad Medical Corporation, Doha, Qatar
|Date of Web Publication||17-Jun-2010|
Director, Non-invasive Cardiac Laboratory, Cardiology and Cardiovascular Surgery Department, Hamad Medical Corporation, Doha
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Hajar R. The artificial heart. Heart Views 2007;8:70-6
| Introduction|| |
In the year 2328, an artificial heart was implanted in the body of Captain Jean-Luc Picard, one of the characters in the American science fiction series, Star Trek. But in 1911, long before Star Trek, the French science fiction writer, Jean de la Hire, had created Nyctalope, a pulp superhero with an artificial heart.
Romance with the artificial heart is understandable because of its potential benefit to patients with heart disease. The idea of replacing a damaged and failing heart with an artificial heart is exciting but so far, its promise is far from fulfilled. Although technology has advanced enormously, the dream of a substitute heart has been elusive. This article is a brief retrospective look at the artificial heart.
| Barney Clark|| |
In December 2, 1982, William DeVries of the University of Utah Medical Center in Salt Lake City, USA implanted an artificial heart - Jarvik 7 - in the chest of Barney Clark, a 61-year-old retired dentist. Barney Clark had chronic congestive heart failure due to primary cardiomyopathy. He also had chronic obstructive pulmonary disease. His condition was progressively deteriorating several months prior to the implant and when he was admitted, "death appeared imminent within hours to days." Clark was not eligible for a heart transplant because of his age and severe emphysema.
When Clark came out of the operating room, his new plastic heart was connected by several tubes to a refrigerator-sized machine. He died 112 days later, of multiorgan failure, but the artificial heart was functioning well.
Although Clark was initially reported to be in stable condition 48-hours postoperatively, his subsequent postoperative course was overwhelmingly complicated:
- 3rd postop day - he underwent thoracic exploratory surgery because of subcutaneous emphysema.
- 6th postop day - he had generalized seizures, which left him in a postictal coma.
- 13th postop day - the mitral valve of his artificial heart malfunctioned, and he was taken back to the operating room to replace the left ventricle of the artificial heart.
- Other complications were recurrent pulmonary insufficiency, several episodes of acute renal failure, episodes of fever of unidentified cause (necessitating multiple courses of antibiotics), hemorrhagic complications of anticoagulation, and respiratory failure requiring tracheostomy.
- 92nd postop day - he had diarrhea and vomiting, leading to aspiration pneumonia and sepsis.
- 112 th postop day - death, which was preceded by progressive renal failure and refractory hypotension.
- Autopsy revealed extensive pseudomembranous colitis, acute tubular necrosis, peritoneal and pleural effusion, centrilobular emphysema, and chronic bronchitis with fibrosis and bronchiectasis. The artificial heart system was intact and uninvolved by thrombosis or infectious processes.
| Congestive heart failure: The problem|| |
End stage heart failure is the main indication for an artificial heart. End stage heart failure is characterized by marked symptoms of breathlessness at rest or with minimal activity despite optimal medical therapy. The incidence of congestive heart failure is increasing worldwide, affecting millions. The condition is characterized by debilitating symptoms, frequent hospitalizations, poor quality of life, and shortened survival. Most patients are treated medically or with surgical therapy tailored to their cardiac disease. Unfortunately, even the most sophisticated drugs and surgical treatments fail in some patients. Life expectancy in severe heart failure with medical therapy alone is less than 50% at one to two years.
For the most severe forms of heart failure with irreversible biventricular failure, cardiac transplantation is the only effective therapy affording longevity and improved quality of life. Survival rates of transplant recipients at one and five years are 94% and 78% respectively. Unfortunately, donor hearts are scarce, and consequently, the majority of heart failure patients wait months and years, and many die before a donor heart becomes available. Hence, a mechanical cardiac device to support the failing heart, either as "bridge to transplant" or "destination therapy" is a necessity.
| Development and application of artificial hearts|| |
- 1957 - Willem Kolff (Dutch-born inventor of the artificial kidney) and his team of scientists at the Cleveland Clinic reported the development and first application of a totally artificial heart in a dog that survived for 90 minutes.
- 1963 - Paul Winchell patents the artificial heart. He invented and subsequently assigned the patent to the University of Utah. It was later used by Robert Jarvik as the model for his Jarvik-7.
- 1964 - Chartering of the Artificial Heart Program by the National Heart, Lung, and Blood Institute (USA).
- 1969 - Denton Cooley of the Texas Heart Institute implants a Liotta artificial heart [Figure 1] in a human patient, keeping the patient alive for 36 hours. The two-chambered device functioned like a natural heart but was powered with enormous air pumps outside of the body, using hoses to pass through the patient's body wall and into the circulatory system.
- 1970s - Development of a variety of extracorporeal and implantable pneumatic ventricular assist devices (VAD).
- 1972 - Robert Jarvik developed the first human artificial heart out of aluminum, polyester, and plastic. He named it Jarvik-3. Cows implanted with this device lived up to four months with little or no medical intervention.
- 1976 - Jarvik improves and refines Jarvik3 and creates Jarvik-7, a two-chambered device made of polyethylene with valves modeled inside. Jarvik-7 ran on compressed air provided by an exterior air compressor connected to the artificial heart by a short, flexible tube. The device kept a calf alive for 268 days.
- 1981 - Jarvik-7 approved for human implantation.
- 1982 - First implantation of a total artificial heart as a permanent device. William DeVries of the University of Utah implants Jarvik-7 [Figure 2] a permanent totally artificial heart in the chest of Barney Clark.
- 1985 - Multicenter evaluation of VADs as a bridge to transplantation and results show potential for long-term support
- 1990s - Transcutaneous technology eliminates the need for skin- protruding electrical wiring.
- 1990s - Patients with long-term VADs recover from heart failure.
- 1994 - FDA approval of VAD [Figure 3] as a bridge to transplantation and first use of a wearable left ventricualr assist device.
- 2001 - The Abiocor Implantable Replacement Heart [Figure 4] is implanted in a patient in the University of Louisville, Kentucky, USA. The patient lived for 151 days (5 months). It has since been implanted in a handful of other patients as well. All patients faced death in 30 days or less from heart failure without the device. One patient survived for 512 days (17 months) after receiving the device.
- 2004 - The CardioWest Total Artificial Heart (TAH) [Figure 5] was approved for use and is the first implantable artificial heart to be approved by the U.S. Food and Drug Administration. The one-year survival rate among patients who received the artificial heart was 70%, as compared with 31% among controls. One-year and five-year survival rates after transplantation among patients who had received the device as a bridge to transplantation were 86% and 64%.
- 2006 - The U.S. Food and Drug Administration approved the Abiocor for use in patients with severe biventricular failure who are not eligible for a heart transplant and who are unlikely to live more than a month without intervention.
| Evolution in design and technology|| |
1982 (The Jarvik-7)
2001 (Abiocor artificial heart)
2004 (CardioWest Total Artificial Heart)
| Limitations of current artifical hearts|| |
The medical and scientific community learned many lessons from the ordeal of Barney Clark and consequently, there have been enormous improvement in design and technology of currently available artificial hearts. But it is still made from non-biological materials such as metal, plastic and polyester and poses many problems such as infection, formation of blood clots leading to thromboembolism, device malfunction, and other complications. The mechanical device also causes damage to red blood cells. In addition, the device requires a power source and current models require the patient to carry an outside battery supply.
| Future directions|| |
Advances in technology have paved the way for smaller, more efficient, and more sophisticated artificial hearts. Teams of scientists from various disciplines, are racing to design the next generation of artifical hearts. But the dream of replacing a failing heart with another that is biologically compatible or as close as possible to a native human heart persists. To this end, scientists are pursuing different approaches through research in genetic engineering, stem cell technology, and tissue engineering. 
| References|| |
|1.||Copeland JG, Smith RG, Arabia FA, et al. Cardiac replacement with a total artificial heart as a bridge to transplantation. N Engl J Med. 2004;351:859-867. |
|2.||Jauhar S. The artificial heart. N Engl J Med. 2004;542-544. |
|3.||Goldstein DJ, Rose EA. Implantabel left ventricular assist device. N Engl J Med. 1998;339:1522-1533. |
|4.||Jessup M. Mechanical cardiac-support devices - dreams and devilish details. N Engl J Med. 2001;345:1490-1492. |
|5.||Jessup M, Brozena S. Heart Failure. N Engl J Med. 2003;348:2007-2018. 6. http://www.biomed.metu.edu.tr/courses/term_ papers/artificial-hearts_gokduman.htm |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]