According to research presented at the American Heart Association’s Scientific Sessions 2008, a collaborative project to develop a device to harness the energy produced by the heart to power an implantable pacemaker is generating great deal of promise. A study of the SIMM, a catheter-mounted generator that can be placed on a conventional pacemaker or defibrillator lead, which uses balloons within the right atrium and ventricle to generate electricity, shows that the technology to develop self powering implantable cardiac devices may become clinically feasible.
From the press statement by the American Heart Association:
In a trailblazing experiment, a microgenerator powered by heartbeats produced almost 17 percent of the electricity needed to run an artificial pacemaker.
“This was a proof-of-concept study, and we proved the concept,” said Paul Roberts, M.D., first author of the study and a Consultant Electrophysiologist at Southampton University Hospital in the United Kingdom. “Harvesting surplus energy might be a major transition in implantable pacemakers and defibrillators because engineers will have more energy to work with.”
In their study, researchers found:
At a heart rate of 80 beats per minute (bpm), the device yielded an average harvested energy of 4.3 microjoules per cardiac cycle. Increasing changes in the heart rate produced corresponding increases in energy. At 104 to 128 bpm, the harvested energy level increased 140 percent. Decreases occurred when the researchers slowed the heartbeat or lowered blood pressure. Implantation and surplus energy harvesting caused no significant injury to the lining of the heart’s chambers.
The innovative generator — called the self-energizing implantable medical microsystem (SIMM) — helps the heart produce more than enough energy with each beat to pump blood.
The SIMM uses two compressible bladders and a microgenerator mounted on the lead of a pacemaker or defibrillator, the wire that connects the device to the heart.
The lead is attached to the end of the right ventricle, and the bladders relay the energy from the pressure of each heartbeat to the microgenerator, which transforms it into electricity for use by the battery.