There could be a new way to be green.
A recent study has opened the door for future pacemakers to run on the extra energy produced by the heart.
In the experiment, it showed that heartbeats produced nearly 17 percent of the energy needed to run an artificial pacemaker.
Researchers also found that increasing the heartbeat yielded a higher energy level and that "surplus energy harvesting" did no damage to the heart chambers.
"Harvesting surplus energy might be a major transition in implantable pacemakers and defibrillators because engineers will have more energy to work with," said Dr Paul Roberts, first author of the study and a consultant electrophysiologist at Southampton University Hospital in the United Kingdom.
He also said the research suggests future pacemakers could last "significantly longer" and more functions could be added to the device to monitor the heart.
One of the major criticisms of current pacemakers is the battery life. Dr Roberts said without the research, the only option to improve pacemakers would be to make them bigger.
The study was presented at the American Heart Associations Scientific Sessions 2008.
Approximately 200,000 permanent pacemakers are implanted in the U.S. annually.