I have been living with NSVT for 3 years, and like you, I worry constantly about it. I get pvc's also. Sometimes I will get 2 or 3 runs of nsvt in a single day, and sometimes I'll only get 3 or 4 a month! I hate how unpredictable these stupid things are, but my doctors have all said the same thing "in a structurally normal heart, it doesn't matter if you have 1 or 100 runs, it WON'T KILL YOU!! I still can't accept that, I have good days and bad days, but I'm slowly starting to believe the doctors. I know how difficult it is, but try and remember that there are people that have this who don't even feel it!! (can't imagine how), and they are still fine, and so are we!! I hope this makes you feel better.
I tend to think the Holter exam was right. I would hope that your test results were not mixed up with another person's results.
NSVT does show up on Holter test, but in the setting of a structurally normal heart, you should be just fine. The fact that you have had a good cardio workup is wonderful. Have you worn a Holter monitor since that time?
There are several of us on the forum who have NSVT and it really is OK (with a structurally normal heart). Try not to worry. If you can't let go of it, talk with your doctor about wearing another monitor. Do you feel any runs now?