Figure 2

Three dimensional Waterfall plots of heart rate variability (HRV) spectra (bin width = 0.005 Hz) illustrate the relative magnitudes of low and high frequency activities on each of four baseline days. Each plot depicts HRV of a representative animal in each treatment group: animals with right stellate ganglionectomy (RSGX) exposed to intermittent hypoxia (IH), sham (SHAM) operated control animals exposed to IH, and time control (CON) animals with no IH exposure. In all plots low frequency activity occurred in the 0.05 – 0.15 Hz band, whereas the locations of high frequency activity were variable depending upon the ventilatory rate. For example, high frequency peaks were located at frequencies > 0.6 Hz for the RSGX animal, > 0.35 Hz for the SHAM animal, and > 0.5 Hz for the CON animal. Note there was an absence of high frequency activity on baseline day one in the CON animal.