A pacemaker is a device that sends electrical impulses to the heart to maintain the proper heartbeat and rhythm.

They are implanted under the skin during a minor surgical procedure to create a “pocket,” and are attached to the heart using wires, also called leads.

Over the years, pacemakers — which were once as large as a cigarette case — have shrunk dramatically to about the size of two silver dollars.

Doctors across the United States are testing a new generation of pacemakers that are just a fraction of that size.

In addition, these pacemakers are implanted nonsurgically, without the use of wires, thus reducing the risk of complications or infections.

The devices were recently implanted in patients in medical centers located in Minneapolis and Ohio; other institutions are expected to follow suit, as companies compete to master this innovative medical technology.

Although conventional pacemakers pose few risks, they can result in complications stemming from implantation, when infections or skin breakdown can occur.

The risk is highest around the lead wires that run from the generator through a vein to the heart. Leads can also break, dislodge, or block a vein.

Although people wearing conventional pacemakers can enjoy active lifestyles, they have to make some accommodations, like avoiding strenuous “full contact” sports or devices that could interfere with its electrical activity.

A conventional pacemaker may also have to be replaced after several years, requiring surgery.

Currently, at least two medical device companies are competing to offer this new, smaller pacemaker technology, which is available only for participants involved in the research studies.

The initial results of the trials are good; I believe this eventually will become the standard of care.