I am 34 years old woman. I started to feel a hard or strong palpitation and bubbles just for seconds. Now are more frecuent. I am no over weight, I eat healthy, the more I can. I work out at least 3 times a week. I used to run 4 miles before without problem. Now I start to feel this at 10 minutes and I.have to stop. I have tiroide problemd (hashoto) but is in control. I went to the doctor but the insurance declained two of 3 tests ordered. I still waiting for the another one. If someone can give me some information, please . Thanks