My heart rate started going crazy 4 years ago this May along with when all of my other symptoms started. At the time I didn't realize my heart rate was skyrocketing until I started checking it with a monitor or got it checked by a doctor. I have been wearing a heart rate monitor watch for the past year or so in order to keep an eye on it. I am currently on 120 mg of Cardizem to slow down my heart rate. My doctor says it actually puts a cap on it so it doesn't get too high. Even though I am on this medication my heart rate can go up to 150 or a little higher just walking around the house or going up the stairs. My resting heart rate is high too. My heart will climb and stay high the longer I am on my feet because I am Orthostatic Intolerant. It didn't used to be this way. I can tell when it is high because I get really dizzy, anxious, shaky, lightheaded, feel like I am going to pass out, more exhausted, and weak. Most of the time I have to take breaks while I am vacuuming to avoid possibly passing out which I definitely don't want to do while home alone with my kids. I am hoping my new doctors will have better ways of coping with this.