My daughter is 5 years old and has, for the past about two weeks, mentioned that her heart feels like it s pounding and fast. I have felt her chest to see if I can feel the pounding and I most certainly can. Her heart feels like it is pounding, as the term goes, out of her chest. The times I have checked it have been when she s doing high energy activities. But the past few times have been when she s just sitting doing nothing active but sitting. I would have to say it feels like it s pounding hard but often than fast, but that it has done both. Is there a cause for concern and what are the different steps I can take for testing to make sure there are no underlying problems?