Abstract: Objective To analyze pathological features of adults with postural orthostatic tachycardia syndrome (POTS). Methods Eighty-two adults aged (38.7±12.24) years who were diagnosed with POTS by head-up tilt test in clinics were selected to constitute the POTS group. Thirty-one adults aged (39.22±10.98)years with negative the head-up tilt test who are excluded POTS served to consititute the control group. History collection and physical examination were done for all POTS patients. Clinical characteristics of POTS adults were summarized. Results There were no statistical differences between POTS and the control group in age, sex radio, supine heart rate and supine blood pressure. About 76.8% POTS took syncope as major symptoms. About 34.14% of them experienced frequent episodes ( >10 times).68 patients had syncope and 19 patients did not have syncope. There were no statistical differences in sex and age between two groups. Most of them have causes before the onset of POTS. The main causes of POTS include postural changes, mental stress, fatigue, exercise, etc. The main symptoms include syncope, dizziness, palpitations, chest tightness,amaurosis, sweet,pale complexion, fatigue. During the head-up tilt test, the HR of patients with POTS increased gradually, and the average maximal HR increase was (45.05±11.06) beats per minute. Conclusion The patients with POTS are usually in all age groups and have a high incidence of syncope. The common symptoms of POST include syncope, dizziness, palpitations, chest tightness,sweet,pale complexion, fatigue. In the head-up tilt test the HR significantly increases in ten minutes and HR increases ≥40bpm.

Key words: postural orthostatic tachycardia syndrome, head-up tilt test, heart rate