Postural Orthostatic Tachycardia Syndrome (POTS)--A novel member of the autoimmune family.

Postural orthostatic tachycardia syndrome (POTS) is a heterogeneous disorder of the autonomic nervous system in which a change from the supine position to an upright position causes an abnormally large increase in heart rate or tachycardia (30 bpm within 10 min of standing or head-up tilt). This response is accompanied by a decrease in blood flow to the brain and hence a spectrum of symptoms associated with cerebral hypoperfusion. Many of these POTS-related symptoms are also observed in chronic anxiety and panic disorders, and therefore POTS is frequently under- and misdiagnosed.