A recent news report suggested that pacemaker patients who used portable music players sometimes encountered a problem with their pacemakers called interference. The problem wasn't with the music player itself, but rather with the earbuds. Earbuds stored close to the implanted pacemaker can interfere with the pacemaker.

This came as a bit of surprise to industry insiders, because the iPod did not have to be on or active for the earbuds to interfere with the pacemaker. Up till now, it was thought that devices turned off or to some kind of passive setting did not pose an interference risk.

What the study looks like is that if a person has a portable music player, such as an iPod (iPod is just one of the best known types but there are many grands) and if the earbuds used with the device are placed in close proximity to the the upper chest area where the pacemaker is implanted, the earbuds might interfere with the device.

This is not a far-fetched scenario. When a person with this kind of portable music player is not listening to it, it's not unusual to drape the earbuds over the neck (sort of like the way doctors "wear" a stethoscope). That can put the earbuds right over the implant site.

Apparently, interference does not occur when the earbuds are in the ears or when the earbuds are kept away from the implant site--such as in a purse or backpack or even hip pocket.

Interference occurs when signals in the air get picked up by the pacemaker. Pacemakers have very "big ears." They listen for electrical signals. In fact, that is how pacemakers monitor the heart--they track its electrical activity and respond to it. While this normally works pretty well, an occasional stray electrical signal can cause the pacemaker to "think" it is hearing something the heart is doing when, in reality, it is sensing electrical interference, something doctors have nicknamed "noise."

Most pacemaker patients are told to avoid the most common sources of interference--things like arc welding equipment, bumper cars, industrial magnets, and being very close to high-tension lines. However, stray signals can sometimes interfere with pacemaker performance. Stray signals can come from small electronic devices (like earbuds), metal detectors, dentists' drills and so on. While such interference is not common, it can occur.

In most situations, the interference does not last very long. The pacemaker may start pacing or acting inappropriately because it doesn't interpret the stray signals correctly, but if the source of interference is removed, the pacemaker typically resumes normal operation. If a pacemaker person starts to feel lightheaded, woozy, or just peculiar in situations where they may be potential interference (around heavy machinery, certain power tools, security checkpoints), just stepping out of range can stop the interference.

Pacemakers are sensitive, but not all that sensitive. A source of interference far from a pacemaker patient does not pose a risk. For instance, most pacemaker manufacturers advise pacemaker people not to "linger" under a metal detector, but pacemaker patients do not have to avoid going near them.

If interference persists over a long time, the pacemaker may do something called "reset" or "backup" or "safety pacing." (This function is more or less the same in all brands of pacemakers except that different manufacturers call it by different names.) When the pacemaker thinks that there is interference is going on and it lasts for a certain amount of time, the pacemaker will automatically revert to a special type of pacemaker behavior that doctors call "asynchronous pacing." Asynchronous pacing is not the most sophisticated pacing prescription, but it gets the job done--it assures regular consistent pacing support.

If a pacemaker patient is exposed to interference long enough to "reset" the pacemaker, he or she will need to go to the pacemaker doctor to get the pacemaker reprogrammed. This is a very short and painless step that involves the doctor turning off the reset function and pushing a button on a remote device called a programmer to resume the old settings.

Pacemaker patients who love their portable music players need to take a few simple precautions. If your iPod is crucial to your lifestyle, you may want to talk to your pacemaker doctor for advice. On the other hand, just keeping the earbuds from your music player away from the pacemaker ... even if the device is not playing or turned off ... you should not experience any "noise" or interference.