Small magnets and mechanical valves

[marc_kowal]

Hi Everyone!

With my new job, I have a name tag that I wear when meeting new clients or hosting open houses. Instead of a clip-on or pin type name tag, this one is a two piece (one part is the magnet and the other is the name tag). It doesn't seem like the company offers any non-magnet name tags. Is there any concern with a small magnet like this and proximity to a mechanical valve? I have a Sorin 25mm Aortic Valve btw. I don't recall anyone posting any issues like this, but i figured I'd throw it out here. Thanks!

 

[pellicle]

Marc
the valves are pyrolytic carbon (and some titanium) and essentially non magnetic, they are even good in HUGE magnets like MRI scans (which I've had a few of now).

no worries mate

 

[marc_kowal]

Thanks for the info Pellicle!

 

[Warrick]

I was sleeping on a magnetic underlay but it was hard to get up in the morning... (joke...cringe) (slept on a magnetic underlay for 2 yrs with mechanical valve)

Before I had my sternum wires out I could get a fridge magnet to stick

 

[Agian]

Before I had my sternum wires out I could get a fridge magnet to stick

omg I've gotta try that.

 

[JWalters]

Don't try this trick with a Pacemaker ! For sure huge magnetic fields can affect these devices, and the Mag field strength is highly sensitive to distance. Despite that my pacemaker is safe with an MRI, I will not be leaning close to high power electric motors, or trying to stick Neodymium magnets on my chest.....

 

[pellicle]

...Before I had my sternum wires out I could get a fridge magnet to stick

Really?

 

[Superman]

Before I had my sternum wires out I could get a fridge magnet to stick

Where did you have your surgery done? Was this before or after a shower (just metal adhering to a dirty sticky guy)?. I can get an MRI with sternal wires still in. Surgical steel is non-magnetic.

 

[Warrick]

Theres a few in this old thread with magnetic wires so its nothing new, although not all are magnetic it seems
https://www.valvereplacement.org/threads/how-many-sternum-wires-do-you-have.6072/page-2

 

[pellicle]

Hi

Theres a few in this old thread with magnetic wires so its nothing new, although not all are magnetic it seems
https://www.valvereplacement.org/threads/how-many-sternum-wires-do-you-have.6072/page-2

well the thing is that AFIK they've never been magnetic so your post is "news to me" (not saying its wrong, but just news).

To the best of my knowledge its because the wires are stainless steel, which is normally not magnetic.

A basic stainless steel has a 'ferritic' structure and ismagnetic. ... However, the most common stainless steels are 'austenitic' - these have a higher chromium content and nickel is also added. It is the nickel which modifies the physical structure of the steel and makes it non-magnetic.​

Stainless has always been used (because, rust) so I thought this went back to even including the wires I had in 1974.

 

[Warrick]

This article on wire corrosion may be of interest
https://www.ncbi.nlm.nih.gov/m/pubmed/16614803/

 

[pellicle]

This article on wire corrosion may be of interest
https://www.ncbi.nlm.nih.gov/m/pubmed/16614803/

I'm pretty sure that's why there's chunks from mine in 1974 still lyin around in my X-Rays ... they couldn't pull it out anymore.

an you can see my little 25mm clicker in there too ;-)

 

[Warrick]

Found this ditty in an old thread-
“Pyrolitic carbon responds to a strong magnetic field, (it's either diamagnetic, retromagnetic or both, I can't rembember, but a sheet of it can actually be levitated over a rare earth magnet.) but I was told by the docs that an MRI doesn't exert enough force to overcome blood flow or pressure, which dictate the position of the valves moment by moment.”

 

[Warrick]

Nuther thread on the magnets, interesting esp Phillip B’s post
https://www.valvereplacement.org/threads/say-it-aint-so.36624/page-2
From what I remember I just used one of those flat sheet fridge magnets, think it was a Charlies Takeaways magnet, they pump out septic tanks , no burgers and fries...
It didnt stick like snap, stuck like on the fridge but it defied gravity and stayed on my chest.
Maybe it was recycled wire from a fence, who knows..

 

[pellicle]

Found this ditty in an old thread-
“Pyrolitic carbon responds to a strong magnetic field, (it's either diamagnetic, retromagnetic or both, I can't rembember, but a sheet of it can actually be levitated over a rare earth magnet.) but I was told by the docs that an MRI doesn't exert enough force to overcome blood flow or pressure, which dictate the position of the valves moment by moment.”

Seems like a minor effect indeed exists.


I quickly glanced a few papers and seems it's related to trace Fe amounts in the carbon. But carbon isn't ferromagnetic, and those are strong magnets very close and the fields fall off at 1/D cubed IE:
If you have a small magnet, the field two feet away will only be 1/8th as strong as the field one foot away.
Thus blood pressure would be significantly stronger (or you've got more serious problems ;o)

 

[afraidofsurgery]

Where did you have your surgery done? Was this before or after a shower (just metal adhering to a dirty sticky guy)?. I can get an MRI with sternal wires still in. Surgical steel is non-magnetic.

I noticed this too once - was with one of the really strong but small fridge magnets, and it didn't stick super strongly but it did hang on. Was pretty cool

 

[Protimenow]

Those magnets stick a lot better if you put a drop of Super Glue on them before testing their attraction to your valve or stainless wires.

 

[pellicle]

I noticed this too once - was with one of the really strong but small fridge magnets, and it didn't stick super strongly but it did hang on. Was pretty cool

so, it seems that at least some of the stainless wires may indeed have some ferromagnetic properties. I guess it depends on the components of the stainless steel wire.

 

[Warrick]

Glue is cheating (and that includes double sided tape, mucus, velcro and pins). ( oh and dirty sticky guys....).

 

[Protimenow]

Yeah, I guess it was a bit of a cheat.