A cardiac pacemaker powered by the heart

London, Sept. 1: Researchers have developed a new batteryless cardiac pacemaker which is based on an automatic wristwatch and is powered by heart motion.

“Batteries are a limiting factor in today’s medical implants. Once they reach a critically low energy level, physicians see themselves forced to replace a correctly functioning medical device in a surgical intervention,” said Adrian Zurbuchen from University of Bern, Switzerland.

“This is an unpleasant scenario which increases costs and the risk of com- plications for patients,” Zurbuchen said.

Zurbuchen has now come up with a way to power a cardiac pacemaker with an alternative energy source — the heart motion.

Four years ago Professor Rolf Vogel, a cardiologist and engineer at the University of Bern, had the idea of using an automatic wristwatch mechanism to harvest the energy of heart motion.

“The heart seems to be a very promising energy source because its contractions are repetitive and present for 24 hours a day, 7 days a week,” Zurbuchen said.

“Furthermore the automatic clockwork, invented in the year 1777, has a good reputation as a reliable technology to scavenge energy from motion,” he said.

The researchers’ first prototype is based on a commercially available automatic wristwatch. All unnecessary parts were removed to reduce weight and size.

They developed a custom- made housing with eyelets that allows suturing the device directly onto the myocardium.

The prototype works the same way it would on a person’s wrist. When it is exposed to an external acceleration, the eccentric mass of the clockwork starts rotating. This rotation progressively winds a mechanical spring.

After the spring is fully charged it unwinds and thereby spins an electrical micro- generator.