Palpitations caused by suddent physical movement?

Hi. I'm a 28 year old male. I consider myself in pretty good shape (lean frame, exercise daily, no caffeine or alcohol, no drugs, eat healthy).

I encountered a strange phenomena today when working out with weights at the gym. I was doing some seated dumbell curls on a bench (30 lbs each arm). When I got up to put the weights back on the rack my heart suddenly began beating erratically (felt like the heat chambers were out of sync and racing/pounding hard) for roughly 3 minutes, then returned to normal. It was pretty terrifying! I'm not sure whether or not to call this palpitations, or something else.

While my heart was beating strangely, I was still able to move normally, no pain, but a bit out of breath perhaps due to anxiety/panic that it caused. I pounded my chest a few times with my hand, forced a few coughs, and did a few stretches to see if I could re-sync my heartbeat.

Anyways, not sure what to make of it all. It was definitely movement-induced, but mechanically not sure what would have caused the irregular beat. When suddenly standing from a seated position, could I have possibly pinched off some blood flow to the heart? Or pinched a nerve? Or maybe due to a quick change in blood pressure?

Thoughts? Thanks!