Here is a link to an interesting study: http://onlinelibrary.wiley.com/doi/10.1 ... x/abstract
"Results– Low frequency power (0.01) and low frequency/high frequency power (0.01) were significantly higher in multiple sclerosis patients independently, all together or in subgroups. Very low frequency (0.01) and high frequency (0,001) power were higher in less affected multiple sclerosis patients. Variability in time domain (0.05) were lower in most affected multiple sclerosis patients. Conclusions– These results suggest that multiple sclerosis causes cardiovascular autonomic dysregulation manifesting as impaired heart rate variability. This illness seems to cause an increase in sympathetic cardiovascular tone; the parasympathetic tone is most variable and depends on clinical and paraclinical findings, but the illness progression seems to provoke a decrease in it."
Obviously, from a CCSVI perspective the conclusion is faulty: it may very well not be MS causing the heart frequency problems, but blood flow problems causing the frequency problems.