The SIMM microgenerator could help power implanted medical devices by augmenting the existing battery for devices such as cardiac pacemakers and implanted cardioverter defibrillators (ICDs). In preclinical testing, the microgenerator successfully produced one-third of the energy required to power a conventional cardiac pacemaker. The consortium is currently discussing next steps for the microgenerator project with medical device manufacturers. Dr. Paul Roberts, consultant electrophysiologist at Southampton University Hospital, United Kingdom, presented details on the SIMM project at the American Heart Association's Scientific Sessions 2008 in New Orleans.
"The microgenerator taps an in-body energy supply - the heartbeat - to help enable more advanced, smaller implanted medical devices that will improve patient care and comfort", stated Martin McHugh, business development manager with Zarlink Semiconductor's Advanced Packaging group and SIMM project co-ordinator. "Taking advantage of a continuous in-body power source, instead of relying solely on batteries, means implanted medical devices supporting advanced diagnostics and therapies can be more easily designed."
Implanted medical devices are increasingly incorporating advanced features in an effort to improve patient care and lower health care costs. For example, cardiac pacemakers are integrating wireless technology to enable home-based health monitoring, with patient health and device performance data transmitted to the physician's office over a broadband network. Wireless technology is also enabling a range of new diagnostics and therapies, including implanted devices used to monitor and treat diabetes and neurostimulators that can alleviate chronic pain or lessen the debilitating effects of Parkinson's disease.
The SIMM microgenerator is a catheter-mounted device that would be placed on a conventional pacemaker or defibrillator lead. The device harvests energy by using differential pressure within the chambers of the heart to drive a linear generator. During testing, the device generated one-third of the power required to run a pacemaker - excluding pacing demand. Next-generation microgenerator devices are expected to fully power both the pacemaker and pacing requirements. Placement of the microgenerator is uncomplicated and is fully compatible with existing techniques for implanting cardiac devices.
"Previous attempts to harvest human energy have resulted in systems that require surgical techniques that pose an unacceptable risk to patients", stated Dr. Paul Roberts. "The SIMM device is designed to be incorporated into a conventional pacemaker or ICD lead, meaning it will not affect current implant procedures for either the cardiologist or patient while delivering a significant clinical benefit. While supporting new applications and functionality, the microgenerator will also improve quality-of-life for patients by enabling smaller devices with a longer operating life."
Announced in December 2006, the SIMM consortium received GBP 560.000 in matched funding from the British government Technology Strategy Board to prototype a device capable of harvesting energy from body movement. The multi-disciplinary consortium is made up of companies chosen for their core engineering skill, product exploitation capability and clinical excellence. The group includes:
- InVivo Technology which helped to evolve and establish the clinical acceptability and feasibility of proposed energy capture mechanisms;
- Perpetuum Ltd. which provided the energy-harvesting microgenerator technology;
- Zarlink Semiconductor which provided advanced micro-packaging techniques at its micro-electronics facility in Caldicot, United Kingdom, and was appointed project leader.