Re: elevated resting heart rate... Chiari related ?
I couldn't tell if they actually diagnosed with your CM or not? If so, they usually rate it from I-IV.
The way you describe it, it would be stage I and that is usually discovered by accident as many people don't have any symptoms at that stage.
And usually any type of heart rate issues are when someone has involved CM at a more aggressive stage.
Did they test you for adrenal gland issues? This is usually done by urine and saliva testing. This can be where there is a benign tumor that has grown and is affecting the glands and release of cortisol/adrenaline. Which then can cause a sudden raise in heart rate for no apparent reason.
An Endocrinologist would be good to see to investigate this possibility.