Figure 5. TPVtd analysis. Poincaré Plots of RR Intervals either n+1 (Left Column) or n+5 (Center Column) or n+25 (Right Column) plotted against n for subject S9. The complexity of the plots diminished during SDB (middle row) and this effect persisted in the first half of the recovery period.
A. Baseline: rather than a simple ellipse, the distribution of RRI was complex at baseline. With two distinct distributions: 1) an ellipse along the line of identity (highlighted in yellow) and 2) clouds paralleling the x and y axes (highlighted in green).
B. Slow, deep breathing: The distribution formed an ellipse which became a circular cloud at higher τ.
C. Recovery: although the distribution and relationship of RRI returned to baseline during the recovery epoch, it was not immediate. Partitioning 20-min epoch in half revealed that for the first 10 min, the Poincaré plot formed an ellipse and in the second 5-min epoch the two distinct distributions resembling the baseline distribution returned.