In this episode, episode 83, I welcome Dr. Jared Miller to the show. Dr. Miller is finishing his electrophysiology fellowship and we discuss the preoperative management of pacemakers and AICDs.
Outline by Brian Park: AICD Outline
15 thoughts on “Episode 83: AICDs and Pacemakers with Jared Miller”
I was curious if you or Dr. Miller could comment on some of the newer pacemakers that have advanced “electrocautery protection modes”. How do these modes differ from asynchronous and what should the anesthesiologist know about these modes?
Similarly, I’ve encountered a few cases recently on pacemaker dependent patients that would be tradionally considered very high risk ie thoracotomy. The pacemaker settings were not changed by cardiology and the explanation was that the newer PPM are much more resistent to oversensing. Is this true and if so why? The explanation I’ve heard is the placement of the anode and cathode within the pacemaker system but it is quite confusing. Thanks and keep up the good work.
Glad you found the episode helpful. Here is Dr. Miller’s response:
1. Regarding “Electrocautery Protection Mode”, this mode is just a name one specific manufacturer gives to have the following effects. For a pacemaker, it makes it asynchronous (AOO, VOO, or DOO; depending on the number of leads). For their ICDs, it turns off tachy therapies and makes the pacing asynchronous (different than when a magnet is applied and the pacing mode is not changed). This mode is nothing new, just a rebranding of existing programming options. You could argue it just makes things more confusing.
2. I’m not sure exactly what the second question is referring to. The recommendations given today are consistent with current guidelines and the practice at our institution. I believe the question is getting at the difference between bipolar (newer) and unipolar (older) leads/sensing. Older unipolar leads (or bipolar leads programmed for unipolar sensing) are more sensitive to EMI. Bipolar leads/sensing isn’t particularly new, so the recommendations given certainly have this in mind.
I hope that’s helpful!
Thanks for another excellent podcast. Dr Miller did a great job explaining everything without the use of visual aids!
Basic question: do all patients need their devices interrogated post op, even if they haven’t been reprogrammed pre op? I’m thinking of straightforward patients with pacemakers who present for reasonably minor after hours procedures. Eg a patient with pacemaker or AICD that’s been checked within past few months, who isn’t pacemaker dependent and undergoes surgery with bipolar diathermy, >6inches away from the pacemaker device. I assume the risk of interference with the device in this setting is low and they can be safely discharged without interrogation post op?
Yes, you are correct, unless there is any concern for malfunction of course.
Great Podcast! This topic is really usefull!
Thanks for a great episode that made things a lot more clear for me.
A question: Should one be concerned about burn trauma to the myocardium through the pacemaker leads if monopolar cautery is used and the electric current runs through the area where the device and leads are located? For example a case of upper extremity surgery on the same side as the device and the electro cautery pad put on the lower extremity.
Dr. Miller says this is not something they worry about or have seen though it is always possible there are case reports out there. In general though, not a concern.
Some more specifics from Dr. Miller: The 2011 Heart Rhythm Society and American Society of Anesthesiologists joint guidelines state “Lead tissue interface damage from an external current is considered an unlikely risk.” I wouldn’t be overly concerned with damage to myocardium and would use the precautions discussed in the guidelines and in our podcast.
Regarding the example given, I recall mentioning this in the podcast. In this instance, I would put the bovie pad on the ipsilateral arm of the surgery, so that the current does not pass by the device.
hello, I’ve fairly recently discovered accrac and really appreciate it. this certainly an excellent topic for and well reviewed for us by Dr Miller. I have a question about electromagnetic interference in neurosurgery. Our surgeons almost exclusively use bipolar cautery so that shouldn’t be an issue, but neuro monitoring with motor and sensory evoked potentials is very prevalent in our cases. I wonder if there is concern for these signals being sensed by the pt’s device? I’m hypothesizing no since the electrical signals in this case are transmitted via nerves.
As far as Dr. Miller and I know this is not an issue, probably due to, as you say, the fact that the signals are traveling through nerves and not through general tissue.
Dr Miller (and Dr Wolpaw of course), Excellent episode , clearly explained and very helpful.
I suspect that the MRI compatibility issue will get more interesting again in the future as with higher field-strengths things will change again. Field strengths in clinical use have progressed from 1.5 T to 3T and will in the future probably increase further. While currently not in routine clinical use especially ultra high field (7Tand up) the lead length is getting uncomfortably near 1/4 wavelength of the Larmor frequency and this can (colleagues did heating tests for external leads and found vigorous heating even when using carbon fibre conductors depending on the wire configuration) cause heating of lead ends due to antenna function and the RF pick-up.
I’m not an MRI expert but I spend 50% of my time working on a Phd in one of the worlds premier imaging facilities and as I’m building things that need to go in the bore it’s hard not to pick up some things about MRI safety.
Thanks for sharing that!
Should an aicd be reprogrammed before central line placement? Or «magnatized»? I’m thinking of risk for inappropriare shock from the guide wire?
We don’t reprogram or place a magnet before central line placement and I don’t think inappropriate shock is a concern. However, I would certainly not place a left subclavian line so as not to damage the leads.