Medtronic Carelink Monitor

Hello to all :)

Haven’t posted for awhile - but come in all the time to read messages and keep up :)

I have a question - I am going to be doing my 4 month remote device check tomorrow morning - I noticed on my antenna that there is no "magnet" icon - does this mean there is no "magnet" and if so, how does this transmit?  I thought that is what the antenna was/is a magnet?  can someone explain to me like Frank or Smitty or anyone:)  Thank you and hope everyone is doing good?  I am 1yr and 4 months with my PM - time has gone so fast since I got my little friend :)

Thanks to all
Blessings
Breezy

7 Comments

Remote Transmission Of PM Data

by SMITTY - 2011-02-15 10:02:23

The remote device downloads the information stored by your pacemaker and converts it to radio signals for transmission to the whatever is receiving the info. There it is then converted back to something useable. I don't recall ever seeing a magnet icon on an antenna as one is not needed for what they do, so I'll have to leave that to someone else to explain.

Good luck,

Smitty

Cell Phone?????

by donr - 2011-02-15 11:02:14

Breezy: Do you have a cell phone? A cordless phone? Both of them are radio devices with antennas. They are just so short that you cannot see them - they are buried within the case of the device. These two devices operate at radio frequencies so high that their antennas are very short. Your PM device obviously operates at a lower frequency that requires a longer antenna, hence you see it.

Now, that being said - every antenna, WHILE IT IS TRANSMITTING, has a magnetic field surrounding it. IT is very, very weak, but radiates outwardly from your antenna to the entire world, getting weaker as it travels outwardly. Your cell & cordless phones do that also. The magnetic field goes right through your head like it isn't even there. THis radio wave magnetic field varies so rapidly it is unbelieveable. That's why it propagates.

OK - on to our little guests in our chests. They do not like magnetic fields - MOF, a stationary magnetic field - that is one that does not vary in time like a radio wave's field, will trip the switch in the PM & temporarily shut it down or change its mode of operation. That stationary magnetic field is generated in the hockey puck they put over your PM to download its memory. It radiates through your chest & the titanium body of your PM like it wasn't even there - but operates the switch inside because it is a magnetic material, like iron or steel.

Now, the radio wave is a) pretty darned weak & b) changing so fast that the switch could not follow it anyway, so it does not affect your PM.

Let me take this to the extreme. Supposing that you went down to the Channel 5 TV tower, climbed all thousand feet of it & hugged the antenna output elements. Same high frequency as your cell & cordless. BUT & this is a very BIG BUT - there are tens of thousands of watts of power in that TV wave & it would probably fry your PM, You really don't want to find out, trust me.

Lemme give you a true experience - it happened to me. About 2 weeks after I got my PM, I had to climb a ladder up into the rafters of my shop. As my chest went between two ceiling joists, suddenly I felt like my PM had been turned off & I darned near passed out. Luckily, I got down off the ladder safely. I sat there & pondered what had happened to me. It struck me - as my chest went between the joists, it passed about an inch from the 240 volt, 30 Amp cable feeding my water heater. The heater happened to be on & the cable had a large enough magnetic field to affect my PM. Every electric wire, while conducting a current, has a magnetic field around it. The greater the current, the stronger the field. So - just don't hug any cables bigger than your desk lamp's wire!

You are safe from the antenna of your PM interrogator,

Now, go out & have a good day.

Cheers.

Don

Thank U:) I think I get it!

by breezy - 2011-02-16 01:02:29

thank u u two...... I understand somewhat... at any rate
I do my PM transmission tomorrow morning..:)
thank you for your replies :) what a story Don :) thank u for sharing it - I won't be doing anything like that for sure
might be of interest to others here too
Take care
Blessings
breezy

Carelink magnet situation

by ElectricFrank - 2011-02-16 02:02:43

The early pacemakers used the presence of a magnet to switch them into a mode where they could be interrogated. Once in that mode the antenna coil could communicate commands and receive results. The later models do not need the magnet for mode switching. They simply use the transmitted signal. The magnet symbol on the earlier antennas actually were required as a warning that they actually contained a strong enough magnet that they could affect other equipment around them.

Now, what confuses the issue is that during the interrogation the pacer is switched into what is referred to as the "magnet mode" even though no magnet is involved.

And then finally, most if not all, pacers do have a magnet sensing switch which provides an emergency room a way to switch the pacer into a safe mode if necessary. Since the ER can't be expected to have a programmer for every make and model available, all they need is a permanent magnet of a standard strength. So if we are in a car accident and need surgery the magnet will set the pacer to something like 55 bpm fixed rate.

By the way I checked my pacer during a Care Link test using a coil of wire looped around the antenna and actually watched the conversation between the pacer and Care Link. Fascinating (at least for an engineer).

best,

frank

breezy

by walkerd - 2011-02-16 06:02:51

I think the antenna picture you are talking about is the automatic symbol that is on the care link, if yours has this symbol it automatically sends info at a set time to a monitoring computor, to my understanding if something out of the ordianary it is sent to your cardio doctor or whom ever you see for pm checks. Im not sure if that is what you are talking about tho.But the above are really good responses.

dave

Good idea

by ElectricFrank - 2011-02-16 10:02:38

It will be interesting to see what your report looks like.

My only problem with watching the conversation is that I don't speak the language. Kind of like listening to the interchange between the Russian and English speaking astronauts on the space station.

frank

Thank u again :)

by breezy - 2011-02-16 12:02:17

wow Frank I think that would be really interesting to watch
the conversation between the pacer and the Care link
neither my hubby or me are engineers so that wouldn't work for me but interesting just the same :)
I always forget to get a print out of my report but today I will call them back and get one.. I want to see what is going on and when I do that I will ask just exactly what some of this stuff means.:)
have a good day to all
Blessings
Breezy

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