Hello. I'm a 30 year old male with a history of fibrous dysplasia of the skull and intractable headache, but no other conditions. In the last 4 years since my headache symptoms increased, I've been not doing too much physically...In my early 20's I was skinny and active but in the last 3 years I gained 70 pounds from all the rest, but I do still get up on the exercise bike 2-3 days a week. Why am I posting a cardiac question, well lately it seems like my heart starts pounding very hard in my chest, I will be mildly tachycardic (maybe 100-110) for several hours at a time, and if I do something physical such as walk up stairs when I'm having these symptoms, my heart will pound *extremely hard* at stay at maybe 130 bpm for a while. But a few hours later, I sort of feel relief all of a sudden and my pulse is normal again. Luckily for me, I live across the street from an emergency room so I just went over there one night at midnight when it started and they told me the EKG was totally normal but I just had some sinus tachycardia, also about $2000 worth of labs were drawn including thyroid tests, and later I had an echocardiogram and chest xray...still normal. Also, I wore a monitor for 30 days, still nothing but isolated early beats. Could this simply be from my physical de-conditioning, or what? I also tend to feel very nauseated and bloated sometimes during this.