Implanted pacemakers have helped millions of people since Wilson Greatbatch accidentally invented them in the 1950s while building a device to record the sounds of a working heart. At that time heart pacemakers were huge external devices and often shocked patients. Greatbatch realized the potential of his invention as an implantable, mobile pacemaker. He spent two years perfecting his design and eventually received a patent for it. Issues with batteries bothered Greatbatch. He eventually started a company to manufacture lithium-ion batteries for pacemakers and at one time produced more than 90% of pacemaker batteries.
Battery issues are an on-going source of concern, including bleeding or infection related to the leads placed in heart muscles, rare battery malfunctions, and the periodic need for a surgical procedure to replace the battery. Researchers at Rice University and the Texas Heart Institute developed a wireless, battery-free pacemaker that runs on power from microwaves. The Rice lab pacemaker receives power from via a wireless transmitter that can be a few centimeters away. Patients would keep an external battery and transmitter in a shirt chest pocket or wear a strap to hold the external component close to the chest near the heart muscle. The speed of the impulses is set by the level of power transmitted. The implanted pacemaker does not need leads to connect the power source, which eliminates the threat of infection or bleeding from lead placement. Because the power source is external, there’s no need for surgery to replace the battery.
The investigators at Rice successfully demonstrated the implantable wireless pacemaker with a pig. They were able to control the animal’s heart rate from 100 to 172 beats per minute. Further study and development by medical and computer scientists is ongoing at Rice, Texas Medical Center, and University of California at San Diego.