I had the racing heart issue on occasion for the last five years when I started using CPAP. It happened more several months back. For about three months I have been taping my mouth and that alone stopped the racing heart. My sleep is also better, not perfect, but a lot better than what I was having. I wear a full mask and for years prior, I was always a mouth breather. I started off slow with the taping. Patches are sold online. I also place the white tape over it so it does not fall off.
