The last 2 decades have witnessed a dramatic and substantial increase in our understanding of illnesses that result from disturbances in the autonomic nervous system. Initially, these investigations were focused on neurocardiogenic syncope. However, it soon became evident that a subgroup of patients suffered from a similar yet distinct type of autonomic disturbance manifested by postural tachycardia, with orthostatic and exercise intolerance as well as fatigue. This disorder has come to be known as the postural tachycardia syndrome (POTS) and appears to be a heterogeneous group of disorders that display similar clinical characteristics.
Blair P. Grubb, MD Postural Tachycardia Syndrome Circulation. 2008 January