It sounds like this is the same thing I started having last summer, and was in the hospital in Dec for it, they call it bigeminal PVC's, but sometimes my heart is 120-130 if I do anything. My heartbeat is between 45 and 115 normally when I have this, which has been 6 days currently. The first cardiologist acted like it was no big deal, said a lot of people had that, after 1 month holter monitor and when I was in the hospital, where my family dr. put me because my EKG scared her to death, that cardiologist said he didn't really know how to help me, so put me on multaq, couldn't do the metroprolol because my heartbeat gets so low and they said beta blockers would make it lower. Got out and went to an EP cardio who said I had 23000 irregular beats a day and he wanted to do the ablation, took me off multaq, he dosen't feel it works anyway, but the day I went for it my heart was perfect so they sent me home. He said he can't ablate something he can't see, they even took me back and forced it to start beating hard with medicine to start the arrhythmia, but it didn't. Now it is getting worse this week and I don't even know if I should call him because when I went back last month, it wasn't doing it again. Anyway, my heart would act better when I excercized also, and when they gave me a stress test it did well also. 5 of my aunts and uncles had pacemakers for supraventricular tacchycardia though so I don't know if that is the old treatment for it or what, I'm confused. Did you see an EP cardio and did they offer you ablation?
If you suffered this arrhythmia enough, the best way for you is to take Supraventricular extra beats catheter ablation. If you did not, take it easy and have a good rest, then you'll find it's gone!