Reply To: P.o.t.s.
The following article is a good discussion about POTS and was updated in January 2017:
https://rarediseases.info.nih.gov/diseases/9597/postural-orthostatic-tachycardia-syndrome
Wikipedia has more good info here:
https://en.wikipedia.org/wiki/Postural_orthostatic_tachycardia_syndrome