Share this article on:

Plutonium-238: An Ideal Power Source for Intracorporeal Ventricular Assist Devices?

Tchantchaleishvili, Vakhtang*; Bush, Bryan S.*; Swartz, Michael F.*; Day, Steven W.; Massey, H. Todd*

doi: 10.1097/MAT.0b013e31826a9204

Ventricular assist devices emerged as a widely used modality for treatment of end-stage heart failure; however, despite significant advances, external energy supply remains a problem contributing to significant patient morbidity and potential mortality. One potential solution is using the nuclear radioisotope Plutonium-238 as a power source. Given its very high energy density and long half-life, Plutonium-238 could eventually allow a totally intracorporeal ventricular assist system that lasts for the patient’s lifetime. Risks, such as leakage and theft identified decades ago, still remain. However, it is possible that newer technologies could be used to overcome the system complexity and unreliability of the previous generations of nuclear-powered mechanical assist systems. Were it not for the remaining safety risks, Plutonium-238 would be an ideal energy source for this purpose.

From the *Division of Cardiac Surgery, Department of Surgery, University of Rochester Medical Center, Rochester, NY; and Department of Mechanical Engineering, Rochester Institute of Technology, Rochester, NY.

Disclosure: The authors have no conflicts of interest to report.

Vakhtang Tchantchaleishvili conceived and prepared the article, performed literature search, and obtained numeric data. Bryan S. Bush performed literature search, participated in drafting the article and data collection, and critically reviewed the article. Michael F. Swartz participated in drafting and critically reviewed the article. Steven W. Day participated in drafting the article, provided literature, coauthored the article, and critically reviewed it. H. Todd Massey provided the idea, supervised the preparation of the article, provided literature, and performed critical review of the article.

Reprint Request: Vakhtang Tchantchaleishvili, MD, Division of Cardiac Surgery, University of Rochester Medical Center, Box Cardiac Surgery, 601 Elmwood Avenue, Rochester, NY 14642. E-mail:

In the past 2 decades, the ventricular assist devices (VADs) have emerged as a widely used modality for the treatment of end-stage heart failure, with significant impact on patient survival.1–3 Despite significant advances in pump technology, which have simultaneously decreased blood trauma while increasing reliability and patient comfort, the energy supply of implantable VADs still remains external. A driveline physically connects the VAD to an outside world, thus contributing to significant morbidity and potential mortality from infectious complications.4–6 Additionally, some fatal pump failures have resulted from electronic fraying of the driveline in modern rotary pumps.7 Even when functioning properly, extracorporeal parts of the VADs result in insufficient usability and suboptimal ergonomics.8 Portable batteries used to power the VADs only provide energy for several hours and must be carried by the patient, thus not allowing full mobility.

Back to Top | Article Outline

VAD Power Requirements

Work provided by the native heart varies between 1 to 6 watts (W) depending on age and physiological state; 1.75 W is often used as an average power.9

For modern rotary pumps, manufacturers report nominal power consumption up to 10–14 W.10 This is several thousand times higher than the power consumed by a pacemaker, which uses microwatts during normal operation and milliwatts for occasional wireless communication.11 Battery- or capacitor-based energy storage technologies are simply not capable of powering blood pumps for more than a few hours and should not be considered as permanent power sources. In contrast, even non-nuclear pacemakers are completely intracorporeal and do not require a driveline with an extracorporeal power source (pacing the heart to pump instead of pumping for the heart).

There are fundamentally three potential solutions to achieve powering an intracorporeal device with these large requirements. The first is a chemical process that uses ingested material to convert chemical energy into electrical energy within the body. Glucose fuel cells have been proposed9,12 and recently successfully implanted in an animal model,13 but the power requirements are very high and the associated technology is only conceptual.

The second potential solution, which has been pursued since the late 1960s14 but is recently being reintroduced,15,16 is percutaneous energy transfer via radiofrequency inductance. Although significant advancement has occurred, this technology has associated problems including the potential to overheat and difficulties maintaining alignment between the transmitting and receiving coils. Percutaneous energy transfer only affects the way the energy is transferred to the VADs (eliminating the need for a driveline), and does not address the insufficient energy density of the batteries. Unfortunately, it may take several years for advances in battery and percutaneous energy transfer technologies to actually affect the VAD patients.

The third potential solution to high-power requirements of implanted blood pumps would be in using a nuclear radioisotope as a power source, namely Plutonium-238 (238Pu). 238Pu is a manmade alpha-emitting radioisotope with a half-life of 87.7 years. Its radioactive decay emits alpha and gamma waves and produces thermal energy that can be converted into useful mechanical or electrical energy using either a mechanical engine or a thermoelectric generator. One milliliter of 238Pu can generate approximately 3.5 W of thermal power. Given this high energy density and long half-life, 238Pu could eventually allow a totally intracorporeal VAD that lasts the duration of the patient’s lifetime. A rigorous selection of this fuel as the ideal choice for this application is included in report by Huffman et al.17

As early as the 1960s, 238Pu was used to power implantable heart pacemakers as well as certain prototypes of VADs and total artificial hearts. A PubMed search of the term “plutonium powered” yields 27 results, mostly published in the 1970s as visualized on the histogram (Figure 1). Although use of 238Pu for mechanical circulatory support never passed the stage of experimentation18–20 and prototypes,21 the pacemakers powered by 238Pu were implanted in hundreds of patients who over the decades developed comparable morbidity when compared with conventional pacemakers, without side effects attributed to the radioisotope.22,23

Figure 1

Figure 1

Back to Top | Article Outline

Design of Plutonium-238 Powered Circulatory Support Systems

Between 1964 and 1973, the National Heart, Lung, and Blood Institute sponsored a well-coordinated development effort of fully implantable nuclear-powered circulatory support systems, including Total Artificial Hearts and VADs. Development efforts of an implantable nuclear source converged on a cylindrical fuel container approximately 1.25 inches in diameter and 2 inches long. This container was capable of generating 50 W of thermal energy (heat), which was converted to useful energy with fairly low (4–7.5%) efficiency engines.24 The temperature of capsules reached as high as 1000 degrees Fahrenheit, so thermal insulation, in addition to the radiation shielding, was clearly required. Researchers identified three primary technical hurdles that had to be overcome, and studies that were fairly convincing suggested that many of the risks were surmountable.

  1. Rejection of the waste heat: Any heat emitted from the nuclear source, which is not converted to useful energy, because of either engine inefficiency or an excess supply of heat, must be rejected from the body. Several groups conducted experiments demonstrating the ability of animals to reject this waste heat.25
  2. Controlling the emitted radiation to levels safe for the local tissue: Extensive modeling,26 benchtop,24 and animal implant experiments were done to predict the dosage of radiation surrounding the capsule as well as the safety of these levels of radiation. Animal models using both unshielded27 and shielded28 sources resulted in apparently normal histology.
  3. A very substantial part of the original design effort decades ago (Figure 2) was on the mechanical engine necessary to convert the heat provided by the 238Pu capsule into pneumatic or hydraulic energy required to drive the pump (Thermo Electron), or the development of a mechanical scotch-yoke system to drive the pulsing ventricle (Atomic Energy Commission pump). The complexity and unreliability of these mechanical engines were perhaps the most difficult engineering hurdles to overcome.25,29 Nowadays, because nearly all modern rotary VADs are electrically powered, the transfer of energy to the pump could conceivably be done with thermoelectric solid-state devices that convert thermal energy to electrical energy based on the Seebeck effect.30 This technology could be remarkably less complex and more robust as compared with the mechanically complex Stirling29 and Rankine31 cycle-based engines of the past.
Back to Top | Article Outline

Safety Considerations

Of course, 238Pu is a very dangerous biohazard and is not free of risks. If used in implantable medical devices, its leakage could pose significant risks to patients and others around them.32 Its ubiquitous presence in assist devices could create a risk of theft and inappropriate use such as nuclear arms.33

Figure 2

Figure 2

In 1978 a Stanford cardiothoracic surgeon, Dr. Eugene Dong, published a science-fiction book called Heart Beat, which tells the story of a dying man who receives a 238Pu-powered total artificial heart, subsequently getting kidnapped by a terrorist who threatens the entire Bay Area with nuclear contamination.34 Of note, the book begins with a quote from Bertolt Brecht’s Galileo: “I submit that as scientists we have no business asking what the truth may lead to.” The book became so popular that it was again published in 1982, clearly showing public concern about this topic.

Given the rising concerns,35 the use of 238Pu was discontinued in implantable medical devices before 238Pu-powered VADs reached the clinical stage. Currently, 238Pu cannot be even used experimentally for this purpose.

Back to Top | Article Outline

Current Applications of Plutonium-238

Notably, more recently 238Pu found its role outside our planet, becoming a preferable nonsolar source of energy in space technology. 238Pu-powered spacecrafts like Gallileo, Cassini, and New Horizons have proven to function very reliably far away from the sun. Most recently we witnessed the launch of Mars Science Laboratory, the most advanced Mars rover to date that has a 238Pu-powered thermoelectric generator (Figure 3).

Figure 3

Figure 3

Back to Top | Article Outline


In summary, 238Pu is an excellent energy source; however, the risks of leakage and theft discouraged the community from pursuing this technology and from approving its use many decades ago. If acceptable system controls could be shown as having overcome these safety risks, 238Pu would be an ideal energy source for this purpose.

Back to Top | Article Outline


1. Rose EA, Gelijns AC, Moskowitz AJ, et al.Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) Study Group. Long-term use of a left ventricular assist device for end-stage heart failure. N Engl J Med. 2001;345:1435–1443
2. Dembitsky WP, Tector AJ, Park S, et al. Left ventricular assist device performance with long-term circulatory support: lessons from the REMATCH trial. Ann Thorac Surg. 2004;78:2123–9 discussion 2129
3. Long JW, Kfoury AG, Slaughter MS, et al. Long-term destination therapy with the HeartMate XVE left ventricular assist device: improved outcomes since the REMATCH study. Congest Heart Fail. 2005;11:133–138
4. Topkara VK, Kondareddy S, Malik F, et al. Infectious complications in patients with left ventricular assist device: etiology and outcomes in the continuous-flow era. Ann Thorac Surg. 2010;90:1270–1277
5. Shoham S, Miller LW. Cardiac assist device infections. Curr Infect Dis Rep. 2009;11:268–273
6. Monkowski DH, Axelrod P, Fekete T, Hollander T, Furukawa S, Samuel R. Infections associated with ventricular assist devices: epidemiology and effect on prognosis after transplantation. Transpl Infect Dis. 2007;9:114–120
7. Jafar M, Gregoric ID, Radovancevic R, Cohn WE, McGuire N, Frazier OH. Urgent exchange of a HeartMate II left ventricular assist device after percutaneous lead fracture. ASAIO J. 2009;55:523–524
8. Geidl L, Zrunek P, Deckert Z, et al. Usability and safety of ventricular assist devices: human factors and design aspects. Artif Organs. 2009;33:691–695
9. Harvey RJ, Bankole MA, Robinson TC, Bernhard WF. Studies related to development of an implantable power source for circulatory assist devices. Am J Surg. 1967;114:61–68
10. HeartMate II LVAS Operating Manual System. 2010 Pleasanton, CA Thoratec Corporation:263
11. Pistoia G Batteries For Portable Devices: Amsterdam, The Netherlands: Elsevier. 2005
12. Kerzenmacher S, Ducrée J, Zengerle R, von Stetten F. Energy harvesting by implantable abiotically catalyzed glucose fuel cells. Journal of Power Sources. 2008;182:1–17
13. Cinquin P, Gondran C, Giroud F, et al. A glucose biofuel cell implanted in rats. PLoS One. 2010;5:e10476
14. Schuder JC, Owens JH, Stephenson HEJ, Mackenzie JW. Response of dogs and mice to long-term exposure to the electromagnetic field required to power an artificial heart. ASAIO J. 1968;14:6
15. Cohn . WE: Tetherless mechanical support—New generation of TETS. Society of Thoracic Surgeons 2012 Annual Meeting. 2012 Ft Lauderdale, FL
16. WiTricity TA. Thoratec announces development agreement with WiTricity for proprietary energy transfer technology [press release].:2011
17. Huffman FN, Kitrilakis SS, Harvey RJ, Van Someren L. A power source for an implantable circulatory support system. Adv Biomed Eng Med Phys. 1970;3:69–88
18. Turner SA, Igo SR, McGee MG, Sterling R, Norman JC. Longitudinal analyses of nuclear fuel sources for thermally-actuated long-term LVAD’s in the primate: a ten-year study. Trans Am Soc Artif Intern Organs. 1981;27:142–146
19. Kiselev IM, Dubrovski GP, Mosidze TG, Bazhanov AI. Prospects for using implanted systems of assisted circulation and artificial heart with a radioisotope power source (biomedical, thermal, and radiation aspects). Artif Organs. 1983;7:117–121
20. Whalen RL, Molokhia FA, Jeffery DL, Huffman FN, Norman JC. Current studies with simulated nuclear-powered left ventricular assist devices. Trans Am Soc Artif Intern Organs. 1972;18:146–51, 157
21. Mott WE. Nuclear power for the artificial heart. Biomater Med Devices Artif Organs. 1975;3:181–191
22. Parsonnet V, Driller J, Cook D, Rizvi SA. Thirty-one years of clinical experience with “nuclear-powered” pacemakers. Pacing Clin Electrophysiol. 2006;29:195–200
23. Chauvel C, Lavergne T, Cohen A, et al. Radioisotopic pacemaker: long-term clinical results. Pacing Clin Electrophysiol. 1995;18:286–292
24. Norman JC, Molokhia FA, Harmison LT, Whalen RL, Huffman FN. An implantable nuclear-fueled circulatory support system. I. Systems analysis of conception, design, fabrication and initial in vivo testing. Ann Surg. 1972;176:492–502
25. Robinson TC, Kitrilakis SS, Harmison LT. The development of an implanted left ventricular assist device and Rankine cycle power systems. Trans Am Soc Artif Intern Organs. 1970;16:165–171
26. Cross FT, Sheppard JC. In-phantom dosimetry of Plutonium-238 circulatory support heat sources. Nuclear Technology. 1972;13:83–94
27. Sandberg GW Jr, Huffman FN, Norman JC. Implantable nuclear power sources for artificial organs. I. Physiologic monitoring and pathologic effects. Trans Am Soc Artif Intern Organs. 1970;16:172–179
28. Pegg CA, Sandberg GW, Lee R, Huffman F, Norman JC. Nuclear power sources for artificial hearts: effects of strontium 90-americium 24-beryllium intrathoracic sources simulating radiation fields of plutonium-238-fuelled circulatory support systems. Br J Surg. 1969;56:617–618
29. Smith L, Sandquist G, Olsen DB, Arnett G, Gentry S, Kolff WJ. Power requirements for the A.E.C. artificial heart. Trans Am Soc Artif Intern Organs. 1975;21:540–544
30. Pustovalov AAL, Lazarenko YV, Shapovalov VP. Small size Pu238-based radionuclide thermoelectric generators: Status, applications and prospects of use. 1989Proceedings of the 24th Intersociety Energy Conversion Engineering Conference Washington, DC IECEC-89:2673–2680
31. Huffman FN, Harvey RJ, Kitrilakis SS. Design of an implantable, rankine-cycle radioisotope power source. Isotop Radiat Technol. 1970;7:171–181
32. Jonsen AR. The artificial heart’s threat to others. Hastings Cent Rep. 1986;16:9–11
33. von Hippel FN. Rethinking nuclear fuel recycling. Sci Am. 2008;298:88–93
34. Dong E Jr, Andreopoulos SA Heart Beat. 1978 New York Coward, McCann and Geoghegan, Inc.,
35. Jonsen AR. The totally implantable artificial heart. Hastings Cent Rep. 1973;3:1–4

Ventricular assist device; Plutonium-238

Copyright © 2012 by the American Society for Artificial Internal Organs