Classical POTS is shown with a rapid rise in heart rate and little fall in blood pressure. The orthostatic tachycardia syndrome is a disabling disease state described at least since 1940 and is the most common reason for referral for orthostatic intolerance in adults. It is an emerging form of orthostatic intolerance in children. With some exception, traditional tests of autonomic function are normal in these patients.
Patients are often unable to hold jobs or attend schools.
Our understanding of its pathophysiology remains incomplete. The central physical finding is upright tachycardia although hypotension and resting tachycardia may also be present. These numbers may require modification for children. Such a response is depicted in the figure. In the case shown, the patient became immediately symptomatic following the start of HUT and required the table to be put down within a very few minutes.