Future pacemakers may be powered by beating hearts

Washington, November 11 : A beating heart may produce enough energy to power pacemakers and defibrillators implanted in cardiac patients, according to a new study.

Dr. Paul Roberts, a Consultant Electrophysiologist at Southampton University Hospital in the UK, revealed that a microgenerator powered by heartbeats was found to produce almost 17 per cent of the electricity needed to run an artificial pacemaker during an experiment.

"This was a proof-of-concept study, and we proved the concept. Harvesting surplus energy might be a major transition in implantable pacemakers and defibrillators because engineers will have more energy to work with," said the first author of the study, presented at the American Heart Association's Scientific Sessions 2008.

He said that the device yielded an average harvested energy of 4.3 microjoules per cardiac cycle at a heart rate of 80 beats per minute (bpm).

According to him, increasing changes in the heart rate produced corresponding increases in energy, with the harvested energy level rising 140 percent at 104 to 128 bpm.

Roberts said that 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, he added.

"What this might mean is that in the next era of pacemakers, you'd get devices that lasted significantly longer and we could add more functions to help monitor the heart. It's possible they could be efficient enough to allow complete and indefinite powering of pacemakers," he said.

Roberts said that the innovative generator, called the self-energizing implantable medical microsystem (SIMM), could help the heart produce more than enough energy with each beat to pump blood.

He revealed that the SIMM involved two compressible bladders and a microgenerator mounted on the lead of a pacemaker or defibrillator, the wire linking the device to the heart.

During his experiments, he attached the lead to the end of the right ventricle, and the bladders relayed the energy from the pressure of each heartbeat to the microgenerator, which transformed it into electricity for use by the battery.

A consortium of companies, which developed and tested the SIMM microgenerator with United Kingdom government funds, is currently working to improve the materials used in the SIMM microgenerator.

"With different materials, we're seeing even greater energy harvesting. While at the moment we see about 20 percent harvesting, we're anticipating that will be significantly more in the next iteration of the device," Roberts said.

ANI