how much could my heart have changed in 10 years?

[Nandorph]

In late 2009, when I was in my early 20s, I suffered from generalized anxiety disorder and would get frequent PACs and PVCs.  It bothered me a lot, so I got checked out by two different cardiologists and both of them came to the same conclusion.  They decided my heart was healthy and that I had nothing to worry about.  They suggested I start exercising regularly and move on with my life, which is what I did.  That year, had about 10 EKGs, one 24 hour Halter monitor and an one echocardiogram around this time.  Maybe this wasn't enough testing?

Between 2010 and 2013, I did a lot of super-endurance exercise, mainly cycling.  I averaged about 20 miles per day cycling and 2.5 miles per day walking.  Since 2015, I also picked up a lot of lifting.  I would get my typical premature beats and skipped beats every so often during this decade, but I ignored them like my cardiologist suggested in 2009.  Recently, my symptoms have gotten more worrisome.  In early 2017, I started to get what felt like couplets and triplets.  I would feel two or sometimes three really quick beats in a row.  Last night, for example, I was lying in bed when suddenly I felt a really quick POP POP in my chest.  I estimated the rate to be 240 BPM.  One time I was just sitting at my desk when suddenly I felt this tickling sensation in my chest and could feel a POP POP POP at a rate of about 140 BPM.  I am basically experiencing couplets and NSVT on a regular basis now.  This has NEVER happened before.  There hasn't been a single day that I haven't experienced couplets since about May of this year.  

Could I have damaged my heart through too much exercise?  Could have made a pre-existing disease worse?  I don't smoke or drink, I have a very healthy weight and I'm *relatively* young at 32.  How much could my heart have changed in the span of my 20s?  

[Careful35]

Have you had NSVT caught on a monitor or are you just guessing that you may be having runs of NSVT?

[Careful35]

I mean it could be that you're having PACS  and not PVCS and having runs of PSVT and not NSVT.

If things have changed and are now worriesome to you, you may ask to be given either a holter monitor if your symptoms happen daily or an event monitor that can be worn longer if they don't.