mendyx

Hi all,
i know someone who has the following symptoms but hasnt been able to get a good diagnosis from docs:
When she does anything even mildly stressful [ie get up from chair, go up stairs, get out of taxi] or sometimes without any precursor at all or without any stress, her heart will start beating very strongly for anywhere from 10-30 seconds up to a few minutes. Very strong racing heart beat, at times for no reason at all. I told her i thought her Sympathetic Nervous system was overeacting somehow or putting out too much adrenaline ie after standing up or going up the stairs ...EKG was normal. Anyone have ideas of a specific disease that causes ONLY increased heart rate to the point of causing panic attack/fear very often ?? Thanks.