I have read here that reflux happens when you take a breath (so don't breathe, I know). To me this indicates that the heart muscle contraction normally there only to pump blood into your lungs, is partly being used to push venous blood the wrong way up your jugulars, to your brain, and that for some reason any valve that should prevent this is open. Breathing and heart beats are not always synchronized, and heart beats are not voluntary.
But your heart responds to a deep breath. Does it beat faster or slower? Harder or less hard?
An operation that restores the valve? It should be open when the brain is draining. Maybe the heart is pumping venous blood toward your brain when you take a deep breath.
I think the red reflux dot I saw on Zamboni's Doppler machine on TV was small, and in the middle. It indicated blood going the other way (pumped by the heart?). So maybe a valve that should be open when you're draining blood from upstairs is sticky any takes too long to open. Or close.
I think many problems can be solved by opening veins. Some of these I have seen pictures of seem to be below the jugulars. That's the kind of thing they should be studying, not whether CCSVI has anything to do with MS. It IS MS.