BPM variability -- arousals?

[ouroborous]

So, I'm just curious. I have the PR System One autopap (just got it) and after a few days mucking around with masks, I finally settled on my old unfriendly combo (the Breeze plus a chinstrap). The machine is showing my AHI to be ~1.5-2.0 with this mask setup, which is, from what I understand, "normal" (with treatment).

I have also been doing pulse oximetry, and here's where the question lies. My pulse ox is decent, never less than 90%, usually around 95% all night long. What I'm noticing, however, are periodic (hourly? -ish?) BPM spikes from my normal sleep heart rate of around 50 BPM to around 90 BPM. These spikes seem to last for about a minute or less.

Are these the AHI's that the machine is telling me about? My SpO2 doesn't seem to drop prior to or during these intervals, which is what has me confused.

Thanks in advance! I've ordered the viewer software for my machine to see if my pulse spikes correspond with the machine's record of respiratory events.