I had my stress test this afternoon. On the treadmill, I went "the distance" and my heart rate was "normally" elevated. Until......As soon as I got off the treadmill and sat down, my heart rate jumped to 200 beats per minute. Looks like I triggered a "condition". Plus, my BP at that time was about 80 over 40.
This happened to me during my stress test too, but I made it only a couple minutes into the test before my heart did a flip-flop then jumped to 219 bpm. No BP measurement though, and I'm curious now if mine was low like yours during these episodes.
Another symptom I sometimes had during multiple episodes was polyuria --I had to pee several times that morning:
https://litfl.com/supraventricular-tachycardia-svt-ecg-library/
"The patient may complain of shortness of breath, anxiety and occasionally polyuria due to elevated atrial pressure releasing atrial natriuretic peptide."
Glad you've had episodes while under observation. Sometimes these things get brushed off as panic attacks or whatnot.