Body Compression in Postural Tachycardia Syndrome (POTS): Effects on Orthostatic Tolerance

Postural Tachycardia Syndrome (POTS) is a chronic form of orthostatic intolerance marked by a significant and sustained increase in heart rate (HR) upon positional change from supine to standing (>30 beats/min [bpm]) in the absence of orthostatic hypotension (<20/10 mmHg decrease). Symptoms must be present for >6 months and other causes of orthostatic tachycardia must be ruled out. Individuals with POTS report orthostatic symptoms including palpitations, lightheadedness, and mental clouding, which improve on recumbence. The vast majority of individuals diagnosed with POTS are women age 13-50 years.

Upon standing, approximately 500 mL of blood immediately redistributes from the thorax down to the abdomen, buttocks and legs. This leads to sympathetic activation as the baroreceptors sense less pressure. In a healthy individual, HR initially increases 10-20 bpm, and the systolic blood pressure (BP) decreases by approximately 5 mmHg. However, in an individual with POTS, this compensatory mechanism is impaired and HR will increase by >30 bpm and remain at this elevated rate for the duration of standing. In some individuals with POTS, upon standing cerebral blood flow velocity decreases. In other individuals, oscillation of cerebral blood flow due to failure of cerebral autoregulatory mechanisms is observed.

Current treatment of POTS involves pharmacological and non-pharmacological intervention including salt and fluid loading, exercise, and physical countermanuevers. There are no approved medications for use in POTS and all use is off label. Compression garments are also often prescribed. Abdominal/lower extremity compression garments provide pressure to the blood vessels in the legs, thighs and abdomen which can minimize blood pooling and lead to improved blood return to the heart. One such garment is the Lifewrap Non-pneumatic AntiShock garment (NASG), indicated in post-partum hypovolemia.

A pediatric study (n=20) found that orthostatic tachycardia and symptoms were decreased during head up tilt (HUT), with the use of a different NASG compression garment vs. no compression. However, there is no data to validate the efficacy of compression in adults POTS, and also no data to determine which type of compression is most beneficial (e.g. lower leg only, abdomen only, combination).

The investigators hypothesize that the use of the Lifewrap NASG compression garment in a fully applied configuration will decrease orthostatic tachycardia and orthostatic symptoms during a 10 minute HUT vs. no compression garment. The investigators will complete a 4-way randomized crossover study of HUTs with compression applied by the LifeWrap NSAG in at attempt to demonstrate decreased orthostatic tachycardia and increased orthostatic tolerance in individuals with POTS. If successful, this study could provide needed evidence that compression in POTS is a successful non-pharmacological treatment modality, and as well, what type of compression is the most beneficial to patients with this syndrome. These findings could rapidly translate to the clinical setting and improve patient care.