Palpitations, tachycardia and breathless

I'm a 22 year old male, 55kg, 5'4 ft. Last year I had an episode of SVT( supraventricular tachycardia), recovered from it with 4 days, All my heart test came back normal, ECG, ECHO, TMT, CECT CHEST, Holter( morbitz type 2 AV block which according to doctors was not significant), but I still have palpitations and feeling of hypoxia/difficulty breathing, my spo2 is usually 96%, my breathlessness is kind of bothering and is making it difficult for me since im an inturn medicine student. I was on beta blockers for three months BD, which was discontinued after that, currently im not taking any medicine.My BP usually remains on a lower side 110/60 mmHg, normal blood sugar, TSH, CBC, LFT,KFT, I had noted one thing that my heart rate rises by more than 30bpm when I stand up from lying position, my doctor suspects that It could be due to dysautonomia and has recommended to go for tilt table test, sleep study, PFTAnd Electrophysiological Study