Personal Injury Law

Heartbeat Extends The Power Of A Pacemaker

By Jane Akre

Using the heart's rhythm as a source of renewable energy may one day be able to extend the power of pacemakers and implanted defibrillators.

Scientists are reporting their findings at the American Heart Association's annual meeting in New Orleans.

Pacemakers work like the heart's "natural" pacemaker. 

A small mass of specialized cells in the top right atrium or chamber of the heart produces electrical impulses that cause your heart to beat.  For the heart to beat properly, an electrical impulse moves down a pathway to reach the heart's lower chambers or ventricles.

An artificial pacemaker, the size of a pager, is implanted in the chest and uses a small battery to help the heart attain a regular rhythm.  When the heartbeat is rapid, most pacemakers have a sensing device that turns them off.

The problem has been the limit to the size and longevity of the battery, which eventually must be replaced every five to seven years.

Southampton University Hospital in the UK has developed a microgenerator -  a self-energizing implantable medical microsystem (SIMM), which is attached to the wire on the pacemaker to the heart and to the heart's right ventricle. 

This test was conducted on a pig because they have similar heart size and function to a human.  The heartbeat pumps energy to the generator which turns it into electricity that is used by the battery.

At 80 beats per minute, the heart generates 4.3 microjoules of energy which translates to about 17 percent of the electricity needs of a pacemaker during each cardiac cycle.  And there appears to be no harm to the heart.

"Wireless technology is relatively power hungry and so there's always a balance you have to strike,'' said lead author Paul Roberts, a cardiologist at Southampton University Hospital in Hampshire, in a telephone interview to Bloomberg. "If you've got an additional power source, it gives you potentially more ability to communicate and to monitor the patient.''

This is just a preliminary study but could replace the need to build a larger battery which is impossible to implant in the human chest.

The next generation of pacemakers with added features, such as tracking blood oxygen levels, temperature and other data, could incorporate the body's own energy to result in longer-lasting devices. 

Eventually energy generated by the body's muscle movements may be captured by implanted devices, Roberts predicts.

Along with British government funding, a consortium of companies was involved in the study including InVivo Technology, Perpetuum, and Zarlink Semiconductor. #

Full post as published by InjuryBoard on November 10, 2008 (boomark / email).