EMC - Electromagnetic Compatibility

I am a brand new member of this club, so do not have the benefit of past discussions. I wonder whether anyone has quantitative information on electric, magnetic and RF (radio frequency) field intensity thresholds for a St. Jude Medical Bradycardia pacemaker? I would like to have field strength limits in Volts/meter, Gauss, mW/cm2, etc., with associated frequencies. So far, I have been unable to get this information from St. Jude Medical.


Wow! What is that?

by pacergirl - 2007-11-21 11:11:05

Hi, I have a St Jude Medical dual pacemaker.

I know what RF is however I have not a clue as to what the other things are, or do, or anything about them. There is someone on this site who might know what this is and can help. Hopefully he will see your post a answer you. I was going to say I was sorry I don't know, but he also told me that "it was okay, I don't have to know about these things!" hee hee. Anyway I will mention your post in case he misses it.
Good luck and welcome!

Pacergirl ;-)

Field intensitivity limits

by NRugg51 - 2007-11-23 12:11:27

I too have a St. Jude pacemaker and wonder what the critical levels of magnetic or RF fields are to have an effect on the pacemaker. I was near an operating MRI and unexpectedly passed out a few days later even though I had had a check-up at the clinic in the interim and was pronounced good. I have not been able to find any information yet.
The FDA makes companies publish complete data about the make-up of drugs, but don't seem to require much detail about medical devices.


EMC Limits

by ElectricFrank - 2007-11-24 07:11:42

Hi, I'm W6DZG and also a biomedical engineer so I understand what you are asking. It is hard to specify an actual working figure since the whole device is buried inside the body. The pacer case is metal so it is shielded as least to most frequencies. The most susceptible thing would be the leads since they act as an antenna to RF fields, but they are buried even deeper in tissue. Magnetic fields are another story. Some of the pacemakers use a sensor to respond to an external magnet, which switches them to a fail safe or programming mode. Of course a strong enough field could raise havoc with one of these especially if the field varied enough to result in rapid switching. My Medronic Kappa 701 apparently doesn't use this method as the remote telephone monitor isn't magnetic.
I haven't had any problem with mine even around transmitters. Early on I deliberately tried mine near several fairly strong sources (with someone available to turn off the source or move me away). I've used all sorts of electric power tools as well. I've fired up a 5W CB with the antenna inside the car. The MRI is a real potent source. It has a very high DC magnetic field as well as an RF magnetic field. I understand that at least some types of leads can actually get hot enough to burn tissue if they are actually inside the tunnel.

hope this helps

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