Pacemakers and Loop Systems

 

by Neil Bauman, Ph.D.

© June, 2014

 

A man asked,

Am I able to use the different loop systems or will my pacemaker prevent my using them?” An audiologist questioned, “Have you ever run into a person who can’t use a loop system due to pacemaker issues? We have some clients that have pacemakers and use loops, but one cardiologist told one guy that he can’t use remotes or a telecoil.

These are good questions and need real answers. Unfortunately, health care professionals generally are totally ignorant about loop systems and seem to blurt out the first thing that comes into their heads without having any real knowledge of the subject.

If a cardiologist says a loop system will interfere with your pacemaker, find out on what he bases his decision. How many people does he know whose pacemakers were affected by loop systems? Can he name even one? Does he have a clue what a t-coil or neckloop or room loop is? Can he point to any research that shows that loops are incompatible with pacemakers?

As one person said,

I can imagine that a cardiologist, having little or no knowledge of telecoils or loop systems, would be biased toward pacemakers and his patients’ health, and thus advise against all neckloop use without having any scientific evidence to back him up.

What’s the truth about pacemakers and loop systems? Here’s what some loop manufacturer’s and installers say.

Ampetronic, one of the largest loop manufacturers in the world, posed this question on their website, “Do induction loops interfere with pacemakers?” They then answered,

A permanently installed induction loop system will not interfere with heart pacemakers if correctly designed and installed. It is possible that interference could occur due to a neck loop as provided with some receivers (for example with Infra-red, FM or similar systems). It is necessary to pin the neck loop away from the location of the pacemaker ensuring 150 mm or 6’’ separation between cable and pacemaker.

Interference could also be caused due to portable loops where the loop cable could be held close to the pacemaker.

The owner of inLOOP, another loop manufacturer, explained,

This is a question that would never get a favorable response from an attorney because there is no way to guarantee there could never be an issue with a pacemaker in an induction field. Pacemakers used to have magnetic switches that could be activated by strong electronic fields like microwaves. The new designs are 100% electronic and should not be affected by a properly installed and tuned loop system.

In other words, the chances of a loop system interfering with a pacemaker are exceedingly slim, but not impossible.

He continued,

I can share an experience we had with a student during one of our commercial loop installation training classes. I was in the process of explaining that the newer pacemakers would probably not have an issue, but if someone were right at the point of transmission there could possibly be more energy and a potential for greater risk.

At this point, one of the attendees who, himself, had a pacemaker, walked up to the commercial loop amplifier that was in use, picked it up and held it to his chest. He smiled and said, “Didn’t do anything to my heart.” His heart was fine, but for a split second mine stopped.

L______, a loop installer wrote,

I have a pacemaker and have asked about loops. I was told that I probably shouldn’t wear a neckloop because it puts the loop within a couple of inches of the pacemaker. However, there are no issues in a looped area, and I certainly spend lots of time in looped venues with no issues.

According to IEC standard 60118-4, the standard governing room loops, the maximum field strength of a properly-adjusted room loop is 400 milliamperes per meter (400 mA/m) (± 3 dB). Since that is the maximum, most of the time it’s well below that.

Is this enough to interfere with pacemakers? St. Jude Medical, makers of pacemakers, in their document “EMI in the Workplace Environment” state, “EMI field strengths encountered above those listed in Table 2 may cause device interference with an undesired device response.” So what is the maximum magnetic field strength their pacemakers are designed to withstand without any problems? The appropriate line in Table 2 reads, “Continuous Wave and/or Modulated Magnetic Fields (50/60 Hz)” shows a field strength limit of “80 A/m peak”.

Now, 80 A/m is another way of saying 80,000 mA/m. So their pacemakers are designed to function correctly in magnetic environments up to 80,000 mA/m. That is a whopping 200 times the power of the maximum magnetic field in a room loop set at 400 mA/m.

Thus it becomes quite obvious that room loop systems are perfectly safe for people wearing pacemakers and have a built-in safety factor of around 200.

The exception might be if the person grabbed the loop wire and held it tightly over their pacemaker, but even then, it may not cause a problem, but I’m not about to bet the farm on it.

Norman Lederman of Oval Window Audio explained,

The subject of pacemakers and induction loop systems comes up from time to time and we have extensively researched the topic, particularly in regard to perimeter area loops because that is what we manufacture.

According to pacemaker manufacturers’ technical specifications pertaining to interference issues, a properly designed and installed area loop (room, vehicle or counter top loop) operating in compliance with the most recent IEC 60118-4 standards will not interfere with pacemakers.

We share this information noting that in our 30 years in business we have heard of only one report in which a pacemaker user felt “uncomfortable” while making use of a room loop. He left the room and felt better. The connection between what he experienced and the room’s loop system was never clearly established.

Therefore, if a person complains of feeling “funny” when near a loop system, he is probably experiencing an anxiety attack, not the baleful effects of a magnetic field on his pacemaker.

Norman continues,

Loop pads and neck loops are a very different story and I personally believe that it is best for pacemaker users to avoid them. Two reasons for this conclusion include:

1. The field strength produced by the loop pad/neck loop is unknown because it is attached to an audio device whose output specifications are not universal or regulated by technical standards.

2. The close proximity of the loop pad or neck loop wire to the pacemaker greatly intensifies the electromagnetic field. Out of curiosity I have hooked up neck loops and loop pads to the headphone outputs of audio devices with resultant field measurements way off the scale re: 400 mA/m.

For interfacing telecoil equipped hearing aids with assistive listening systems, I generally recommend area loop systems because the field is diffused and consistent, with much lower average & peak levels in comparison to loop pads and neck loops.

John Woodgate, one of the world experts on loop systems, explained,

With neck loops you have to be very careful where you measure the field strength, because for any loop system the field strength gets very high near the loop wire.

This is why I have suggested a “looped hat” for people with pacemakers. That should ensure that there is no possibility of affecting a pacemaker, unless you take the hat off while it’s working, and clutch it to your chest, of course.

Loop pads are a bit different. The same principle applies that the field strength is very high near the loop conductor, but it can also be very high elsewhere.

This is because the loop is quite small, and the listening height is very large in proportion. So to get enough field strength at the ear height, the field strength even several inches above the pad is much higher. This also applies to chair-seat loops, which may be a bit bigger, but the listening height is also a bit bigger.

What this all means is that room loop systems should not pose any risk for a person wearing a pacemaker. The same holds true for people using Music Links and equivalent devices since the power in them is so small and they are kept at ear level.

Where a problem may arise is if you wear a neckloop, or sit on a loop pad or get too close to a counter loop or portable loop. In these cases, to guarantee your safety, you probably want to keep some distance between the loop wire and your pacemaker. As mentioned above, for neckloops, they recommend a safe distance being 6” (15 cm) or so.

If you have a loop pad (seat pad) and place it on the floor or under your seat cushion, likewise, there should be no problem as the field strength rapidly decreases as the distance increases.

However, there may be a problem if you put the loop pad on your headrest instead of sitting on it. That way it could be too close to your pacemaker, so you could conceivably have a problem.

And of course, if you have a pacemaker, never clutch a loop wire to your chest, or lay on the floor right over a loop wire.