chart-poincare-plot
A four-state Poincaré return map for heart-rate variability that derives SD1, SD2 and their ratio from the raw RR series in the 45°-rotated frame, draws the fitted one-SD ellipse about the cloud's own centroid on a forced-square equal-scale plot, and forms pairs only from beats the recording's clock agrees are successive.
chart-poincare-plot
A four-state Poincaré return map for heart-rate variability that derives SD1, SD2 and their ratio from the raw RR series in the 45°-rotated frame, draws the fitted one-SD ellipse about the cloud's own centroid on a forced-square equal-scale plot, and forms pairs only from beats the recording's clock agrees are successive.