Rubecofi:
Today while doing Plyometrics, as usual my heartrate skyrocketed. It was strong at 150 bpm and then quickly upped to 173.
Well, since you are 33, your max HR is about 187 so you were at 92% of HRmax. That alone, IMO, is not an issue but the "fluttery feeling" may indeed be reason to get it checked. Also, 150 is only 80% of your HRmax and so shouldn't be cause for concern, assuming there are no congenital issues.
One question is did you "panic" when your HR was that hight and didn't drop as expected, as such an emotion could have an effect too.
Also, did you try pacing the floor and taking deep slow breaths to bring your HR back down.
In the early days of P90X Classic my HR was occasionally up to 155 (my HRmax is 157) so I pressed pause and paced the floor breathing very deeply till it dropped into the low 140s and proceeded. I didn't experience any symptoms other than very heavy breathing so felt it was OK. When doing cardio I shoot for 90% HRmax, while circuit training my goal is around 80% HRmax.
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