Are mechanical valves affected by magnetic objects nearby, or by MRI's?

[CATDOG]

I read a brief article about Ipad2 having magnets that could affect brain shunt settings when in close proximity. So now I'm wondering if there are any magnet problems with mechanical valves. Can the leaflet function be attracted/affected by magnetic sources?

 

[yotphix]

Short answer: No. The valves are not affected by MRI, or by nearby magnets. The material itself has the peculiar property of being (if I recall correctly) 'retromagnetic'. You can take a sheet of pyrolytic carbon and levitate it with some good strong magnets, but the haemodynamic forces which operate the flaps are much stronger than any magnetic effect could be.

 

[chaconne]

catdog,

The On-X aortic valve I have is claimed to be able to be safe in an MRI with a magnetic field up to 4.7 Teslas, however other docs I saw set it at only 1.5 Teslas not including time-varying effects. I'm not sure what the range of MRI field strengths are. Below is an earlier thread that may be useful

http://www.valvereplacement.org/forums/showthread.php?20345-MRI-and-mechnical-valves

 

[sarahsunshine]

That's what I read too - but Skyler's cardiologist will not give MRIs to patients with prosthetic valves. He says that there's "metal beneath the outer carbon"

 

[thomas999]

I have a St. Jude MV made of pyrolytic carbon and have had two MRI's so far. Yes, the MRI techs freak out a little not knowing themselves if it is safe, but with the right paper work they complete the tests.

 

[dtread]

Looks like 3 Teslas or less for mechanicals:

St Jude: http://www.sjmprofessional.com/Prod.../Safety Documents/MRI Safety Information.ashx

On-X: http://www.onxlti.com/heart-valves/medical-professionals/mri-memo/

Sorin: http://www.sorin.com/sites/default/..._and_Annuloplasty_devices_MRI_Information.pdf

Medtronic: Could not find info on the Medtronic mechanicals