On propranolol for pots heart palpitations which sometimes helps and sometimes dosent. can the pots heart palpitations lead to any serious cardiac events left untreated? all heart tests came back normal. heart rate is normal when laying down/sitting?

The rapid heart rate seen in POTS is simple sinus tachycardia which isn't a serious tachycardia and isn't usually longlasting especially with a beta blocker on board. POTS often disappears in time. Some researchers consider it an autoimmune disorder but most regard it as a dysfunction of the autonomic nervous system. Have you consulted a cardiologist with a special interest in POTS?