Figure 3. Heart rate variability measured before and after oxygen desaturation events at baseline (dashed lines) and after 12 months of treatment (solid lines).

Heart rate variability parameters did not differ pre-oxygen/post-oxygen desaturation events or after 12 months of treatment. Error bars indicate ± 2 standard errors. HF = high frequency, LF = low frequency, nu = normal units, SDNN = standard deviation of NN intervals.