Heart pacemakers and vibration

[Simon Lewis]

All,

 

I've only recently become aware that certain pacemakers can respond to external vibration in order to match pacing with physiological activity.

This has led to a reduction of the level of low frequency sound in a church music group's mix so as not to cause discomfort to the person fitted with the pacemaker. I'd be interested if any others have encountered this issue, and if so, and the response they have taken.

 

Thanks,

 

Simon

[matt_beal]

Hi Simon,

 

I don't have time right now to do any decent research on this, but if it helps the type of pacemaker you are looking for is referred to as a "Rate Responsive VVIR Pacemaker." The model that popped up straight away for me was the Activitrax pacemaker made by Meditronic which has been around for decades. As you say it works by sensing vibrations associated with exercise and increasing the pacing rate.

 

A quick search on Goggle Scholar hasn't produced any relevant research relating to sound interference with these devices. I looked at a couple of studies from the early 90s looking at how in flight vibrations effect the units. Naturally, an increase in pacing rate (to about 105bpm, so not that fast) was observed during helicopter flights and the authors hypothesised that there were ways of preventing problems during flights, but didn't expand.

 

I am surprised that vibrations from a PA, especially in a church, could be enough to cause an increase in heart rate large enough that causes discomfort. From initial literature searches your problem doesn't seem to be one that has been particularly well documented, and certainly wasn't something that was highlighted when I studied cardiology. It would be interesting to hear if anyone else has any experience of this too.

 

Out of interest, what do you mean by "discomfort"?

 

I will try and do some more thorough lit searches when I have a bit of spare time.

 

All the best,

 

Matt

 

P.S. The person you talked about ought to have their pacemaker checked, just in case... :D

[kerry davies]

Agree with Matt that checking the pacemaker is necessary, a pacemaker user site at; http://www.pacemakerclub.com/public/jpage/...5471/content.do

virtually says that unless you sit on top of really big speaker magnets there is no problem.

 

It can happen but is apparently a matter of response rate adjustment and there is even a post from a newbie on there who had a "moving" religious experience similar to your groups'. He just moved away from the speakers and "cured" it.

[J Pearce]

Is it possible it is related more to the magnetic field of the hearing loop than the acoustic vibrations of a pair of twin 18s?

[Simon Lewis]

Is it possible it is related more to the magnetic field of the hearing loop than the acoustic vibrations of a pair of twin 18s?

 

No - this isn't a magnetic issue (although ISCE and others have discussed the effect of AFIL systems etc. on pacemakers).

 

This is one fairly young individual who feels unwell if there is "significant" bass content. To put it in context, that's MOR contemporary church service bass levels (at most 90dB(A), 95 dB©).

 

Simon

 

A concurrent post has been automatically merged from this point on.

 

I will try and do some more thorough lit searches when I have a bit of spare time.

P.S. The person you talked about ought to have their pacemaker checked, just in case... :D

 

Matt,

 

Many thanks for this! I will try and chat with the individual concerned to find out more details...

 

Simon

[the kid]

I believe there is a difference between unwell, and pacemaker being weird.

 

I have a friend who had one fitted that decided to play up about every 3 hours or when he was resting for a long period, this "play up" delivered a mighty jolt until he could see the doctors.

 

From that and my nan's old pacemaker if it is going to be a it weird, it will be WEIRD.

 

I would also suggest after the xmas hols doing a tad of research and giving a specialist a bell / email and ask if they know of any issues.

[phawthorne]

I 'm not a cardiologist but I come across pacemakers regularly - I'm an anaesthetist. The sensing mechanism for rate repsonsive devices is NOT simple vibration, it's neuromuscular sensing. I don't want to be overly emphatic here but it is really HIGHLY unlikely that the vibration we are discussing from speakers could affect the pacemaker. In theatre (sorry, my kind of theatre ) we are much more concerned about magnetic fields and high frequency radiowaves.

 

If the individual is really feeling serious discomfort I'd be asking is this actually an implantable debrillator delivering a shock?

 

Not often I come across a topic in this forum I actually know something about!

[boswell]

we are much more concerned about magnetic fields and high frequency radiowaves.

 

Not often I come across a topic in this forum I actually know something about!

 

What frequency RF are you talking about, 800Mhz, 2.4Ghz, 5Ghz or higher?

[phawthorne]

What frequency RF are you talking about, 800Mhz, 2.4Ghz, 5Ghz or higher?

 

It varies, 100's KHz to 5Mhz.

 

So high frequency current in the radio range as opposed to "high frequency radio current".

 

Our main concern is surgical diathermy, where surgeons use a high voltage, high frequency current to cut/coagaulate. The voltage is in the hundreds and the high frequency is well above

any of the physiological waveforms - in particular cardiac muscle activity. There are lots of strategies for using diathermy relatively safely with implantable cardiac devices and in reality the risk of causing

faults or inappropriate behaviour is very low. In 25 years of practice I've never seen a problem. (Damn!. Says that at the start of a new year!!).

 

So back on topic, it's unlikely that simple mechanical vibration is playing a part in the OP question.

[boswell]

Thanks for that, the way I read your post, I was thinking more about Radio mic transmitters close to the chest!

 

So I take it that there should be no problem with 2.4ghz 10mw tx mounted in a bra!

I won't hold you to your answer B-)

[phawthorne]

Thanks for that, the way I read your post, I was thinking more about Radio mic transmitters close to the chest!

 

Well the frequency used is not to avoid implantable pacemaker problems, it's to prevent electrocution by inducing fibrillation in the heart which would happen at much lower frequencies of course, like 50-60Hz. I really don't know what advice people with implantable devices would be given about wearing transmitters - this would be very much the province of cardiac technicians.

 

Again we're a little off topic but if you are keen to persue this I'll have a chat with our cardiology department - they owe me B-)

 

Actually this is becoming a more frequent occurrence, implantables are cropping up in all sorts of cardiology/epilepsy conditions now; it's not just granny with her dicky heart!

[matt_beal]

The sensing mechanism for rate responsive devices is NOT simple vibration, it's neuromuscular sensing.

This was my initial understanding until I did a few background searches:

 

The ability of externally strapped accelerometer(Excel [Cardiac Pacemakers, Inc.]) and vibration-based (Activitrax [Medtronic, Inc.]) rate adaptive pacemakers to... SNIP

(Bold is my addition)

 

Surely if the pacemaker is based on accelerometers etc, then thats not neuromuscular sensing? It's my understanding that most pacemakers have an "On Demand" or "Synchronous" setting that works in the way you describe...?

 

I'm perfectly willing to be proven wrong... it's what being a med student is all about!

 

All the best,

 

Matt

[phawthorne]

The sensing mechanism for rate responsive devices is NOT simple vibration, it's neuromuscular sensing.

This was my initial understanding until I did a few background searches:

 

The ability of externally strapped accelerometer(Excel [Cardiac Pacemakers, Inc.]) and vibration-based (Activitrax [Medtronic, Inc.]) rate adaptive pacemakers to... SNIP

(Bold is my addition)

 

Surely if the pacemaker is based on accelerometers etc, then thats not neuromuscular sensing? It's my understanding that most pacemakers have an "On Demand" or "Synchronous" setting that works in the way you describe...?

 

I'm perfectly willing to be proven wrong... it's what being a med student is all about!

 

All the best,

 

Matt

 

 

No, questioning received information is what being (any kind of) student is all about!! In your case exposing a gap in a consultant's knowledge gracefully is to be commended B-) Have to say I have never, ever, come across the use of accelerometers for this purpose. I note the paper you quote is from 1995 - more research needed by both of us!

[Simon Lewis]

Many thanks for the information given so far! I shall follow up the references and have a chat with the pacemaker owner.

 

In the meantime, a colleague whose fiancee has a pacemaker told me, "Meditronic VVi setting reacts to vibrations, predicting body movement and as such increases or decreases the amount of pacing in prediction of activities such as running.... Its possible to tap the pacemaker site and give someone a BPM of 110, its rather funky playing with peoples hearts like that..." (my emphasis).

 

Simon

[RoyJ]

Hi there, I have been fittered with a implanted neurostimulator or pain pacemaker.This is wired to my spine but is a simular device.The main concern is as has been said before that of magnetic fields and to a lesser extent RF.I am also a licensed radio amateur and encounter no problems with Rf from 0mhz to 433mhz.The only problem, I can see with vibration is if it caught me unawares causing me to jump,then I would get a voltage spike due to the electrodes moving either closer or further away from the spinal cord.A cardiac pacemaker senses the electrical activity of the heart and as such should not be effected by vibration,since the electrodes are connected to the heart,picking impulses up from the SA node to the Av node and then down the bundle of HIS to the purkinje fibres in the ventricals.So in my humble opinion, I would be more likely to be effected due to sudden movement rather than the actual vibration itself.To give you some idea, I get an electric shock when I cough,sneeze,laugh,or even pass wind all due to internal electrode placement.I also have to avoid diathermy and MRI scanners,and certain door security systems.Hope this helps,Roy (also a ambulance technician),Technical manager