Yes; I went through something similar. I just fell apart on the bike although I didn't experience the flutter, just the missing beats. My doctor said if I weren't an athlete I probably wouldn't have noticed it and it wouldn't have been an issue.
The missing beats are called
Wenckebach Heart Block.
I have a pacemaker implanted. It took a year for the cardiac doc to get it to work after a lot of expensive testing, all for want of one lousy checkbox in the software! If that happens to you, tell the doc to change the state of the PMTI,
Pacemaker Mediated Tachycardia Intervention.
Tip: If you go to the E.R., tell them you have heart issues. You'll get the Platinum treatment, even though you'll probably be fine in all appearances to them. That's what my PCP told me to do. I was treated faster than any dictator!