My 15-year-old daughter, under treatment for Atrial Tachycardia, has been complaining of her heart pounding "too hard" to where she feels pressure in her head and feels/hears the beats. Is that normal? She's also experiencing headaches. She's on medication and seeing a cardiologist...will follow up with him again tomorrow for her latest holter monitor test. The symptoms occurred yesterday, and she was NOT exerting herself, just walking with me through the store. It's kind of freaking her out.