Agree that it's worth mentioning to your doctor next time you see her.
Quite a few people have asymtomatic atrial fibrillation; it can cause problems, and it can progress to symptomatic Afib. Your doc or the cardiologist he refers you to may decide it's a good idea to put you on medication to address it. Until or unless presumptive Afib starts happening a lot, I'm not sure it'd be worth the fancy sensor and 24 hour test, just because the odds are against catching it during the monitoring period.
Two more suggestions (from a non-medical person). First, hand on to the file from that ride (.fit or similar). Second, if you see a recurrence of this phenomenon, plan to see your PCP quickly. Ask for a referral to a cardiologist who's athletic, and take that doc both files.
And since I can't count gud, make sure your HRM battery is fresh, and consider using it with electrode gel to try to reduce spurious peaks.