My 13 year old daughter has been experiencing rapid heartbeat when walking upstairs or even down the halls at school. I have taken her to ER twice and heartrate was between 110 and 120 but they did EKG and blood/urine tests and all they found was ketones in urine and said it was dehydration . She had no reason to be dehydrated. Her hands and face also felt numb and her hands were clenching. They gave her fluids and sent her home. I took her to her pediatrician who suggested anxiety and did nothing more for her. She eats healthy and drinks plenty of fluids. She continues to experience this fast heart rate and feels like her heart is beating out of her chest with very little activity. What should I do at this point and what could be causing this?