I'm 24, female, and normal height and weight. Up until May, I was using an elliptical at the gym and had no problems exerting myself in any way.
It all started three months ago when I had episodes of palpitations (I could feel my heart pounding in my chest) and my pulse rate skyrocketed. I ended up seeing a cardiologist, who did an EKG, ECG, and stress test. He also put me on a halter monitor for ten days. The monitor picked up on a sinus tachycardia and the doctor eventually diagnosed me with a trace of mitral valve prolapse but said it was so insignificant that it shouldn't be causing me any problems.
Later, I saw a pulmonologist who performed a spirometry test which came out normal. Since I had a chest xray one month earlier, he didn't think I needed another one. He listened to my lungs and decided my problem wasn't pulmonary. He walked up two flights of stairs with me while I wore a pulse oximeter. My heartrate went from 84 to almost 160. At that point, he realized something had to be going on but he wasn't sure what, since I'd already seen a cardiologist.
I saw a second cardiologist this past Friday, who did an EKG and ECG. He called me this morning and told me my ECG looked normal and that he doesn't even think I have mitral valve prolapse. He thinks I could have sinus tachycardia, but wants me to go in for a stress test next week to be sure.
Structurally, my heart is fine, but clearly there's something going on. Today I walked up two flights of stairs while carrying a small bag with my laptop in it (I've never had a problem with this before) and my heartrate jumped to 160. I felt short of breath and like I was going to pass out. It took over twenty minutes before my heartrate came down to 110, and during that time I felt intense chest pain. On a typical day, my heartrate is above 95 and easily goes up with the smallest amount of exertion, whether I'm walking around or doing chores around my house. The doctors claim it's fine and nothing serious, but how can it not be when I'm experiencing all these problems with everyday activities? I suppose I'll have to wait and see what the results of my stress test are.