Differences in heart rate variability (HRV) among different cardiac preparations (baseline conditions).

<p>A to D, Tachograms from: (a) human normal sinus rhythm (n = 72); (b) human congestive heart failure (n = 44);(c) rabbit SANC(sinoatrial node cell; n = 67);(d) conscious rat(n = 11) subjects. Individual experiments are plotted in unique colours. E to J, Summary of baseline differences in cycle length (CL) and HRV among cardiac preparations. Mean (+SEM) CL (E,H), SD of normal beat to normal beat intervals (SDNN; F,I), and root mean square of successive differences (RMSSD) (G,J) for different preparations.