>>> John Boone on Biofuzz 
 WE> But why plot 60/(Pulse Interval)?  The 60 is most likely because of 1 
 JB> For example if the time for one beat to the next beat is 
 JB> .5 seconds, P-P interval is .5 seconds, the persons heart 
 JB> rate is 120 beats per minute, (60/.5). 
I see, since the P-P interval is less than one the reciprocal transformation 
exaggerates the spread.  As the critical focus is zero spread, this data 
transform is more accurate than the simple:
 JB> I am interested in Heart rate, however, one could just measure 
 JB> the P-P interval variability as well. 
 JB> IAE, make up some heart rates and plot it on a x-y 
 JB> graph, here are some realistic ones.  HR1=80, HR2=75, HR3=70, 
 JB> HR4=85, HR5=90, HR6=72, HR7=65, HR8=75, .... 
 JB> Point 1 is (80,75), point 2 (75,70), point 3 (70,85), 
 JB> point 4 (85,90), etc. 
  7 8 9
7  2
    1
8 
  3
9    4
Hm, it's doing more than just checking the deviation of distance(HRi' - HRi) 
i' = i+1.  It's checking meander.  How conceptually does this compare with 
the deviation of the data set HRi?  There's some sort of smoothing going on?
 JB> I think they are pretty and graphical representation is 
 JB> easier to "see" for me.  
Point made.
 
 WE> Don't get the pendulum example, too complex.  How about a 
 JB> Think of a simple pendulum with the pivot point fixed. 
 JB> Now move the pivot point horizontal say with a certain 
 JB> omega, frequency.  
 JB> Does that help? 
Oh a simple one dimensional oscillation?  The amplitude would slowly 
diminish.  As the pendulum approached center the spread area would approach 
zero.  No?
 WE> drummer, thump, thump, thump or a typist, click, click, 
 WE> click. 
 JB> 
 JB> Not really sure how to do this. I'll think about it. 
 
 WE> Hm, what about fibrillation and other erratic heart 
 JB> Hard one for me to answer, in particular. But I can 
 JB> answer ventricular fibrillantion, VF.   VF does not plot 
 JB> out "choatic", interesting no. 
Is this quiescence during or before a VF attack.
 JB> Of interesting note, if one looks at EEG, electro-encephalo 
 JB> graph, activity, brain activity, the plot becomes very 
 JB> non-chaotic just before a seizure, interesting no. 
Hm, going back to the example of the pendulum, something is coming to a 
standstill.  Now consider a moving marble moving around a shallow funnel.  
It's spread approaches zero as it nears the center and if there's a big enuf 
hole in the center ...
 WE> Plot domain?  The smallest rectangle with sides parallel to 
 WE> the axis that contains all the plotted points. 
 JB> Yep, the plot, even though choatic, is constrained within 
 JB> limits on the x,y plane.     
My think tank has sprung a leak. -)
 
 WE> I've heard it rumored some years ago that medical students 
 WE> are mathematical shy.  Is that so?  Are you in medicine or  
 WE> biology?  Are you considering a fuzzy thesis or research 
 JB> Some are, some are not.  I was once a medical student. 
 JB> Medicine. 
 JB> Research while working leaving little time for research.  
So you're a mathematical literate doctor that would like to do research 
except for lacking funds?
... H2O hydrogen oxide, HOH hydrogen hydroxyl, or OH2 oxygen hydrate?
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