Poincare plot for hrv

Hello, I'm writing an application to analize HRV and I have a problem with the Poincare plot. I've done the SD1 and SD2 parameters but I don't know how to vizualize the plot. Can anybody help me in this matter? I'll be very grateful ;)

that is what I've done:

%Poincare plot
xp=odstepRR;
xp(end)=[];
xm=odstepRR;
xm(1)=[];

%SD1
SD1 = std(xp-xm)/sqrt(2);
set(handles.sd1, 'string', num2str(SD1*1000));

%SD2
SD2 = std(xp+xm)/sqrt(2);
set(handles.sd2, 'string', num2str(SD2*1000));

%SDRR
SDRR=sqrt(SD1^2+SD2^2)/sqrt(2);
set(handles.sdrr, 'string', num2str(SDRR*1000));

[David]

can you plz explain how you arrived at the sd1 and sd2 equations?

Answer 1

[bym]

I don't know what the variable odstepRR is, but a reasonable assumption would lead to this as the Poincare plot

plot(xm,xp,'.')