Fig. 3.

Illustrations of a time series of heart beats (R-R intervals) from a normal individual (A) and of animating TPVa in Poincaré plots for heart beats (R-R intervals) from a section (circled in A) of that time series (B). A: periods in seconds of sequential heart beats (solid line) and the data underlying TPVa (dashed line) are plotted as the distance from the origin. Circled area shows the portion (151–195) of the time series from which the analysis in B is taken. B: screen shots of the animated TPVa Poincaré plots for the heart beats between 151 and 295. Every 20th Poincaré plot is shown, all the points for n+1 vs. n (n = 1,142, light gray circles), the 25 points (w = 25, dark-gray solid circles) being averaged (NOTE 4-point overlap in the selected screen shots), and a TPVa data point (black solid circle). TPVa data points form the black dashed line in A. With this number of points being averaged, TPVa moves along the line of identity. The coefficient of variation for TPVa correlates with SD2.