Abdominal and Lower Extremity Compression During Tilt Table Testing in Adolescent POTS Patients

Postural orthostatic tachycardia syndrome (POTS) is a common cause of orthostatic
intolerance in adolescents and adults. Compression stockings are commonly recommended as a
treatment modality for POTS, but the effects of abdominal and lower extremity compression
during tilt table testing have not been measured in adolescent patients. The aims of our
study are to compare heart-rate changes and symptom onset during tilt table testing (a) with
and without abdomen/lower extremity compression and (b) with abdominal compression only
versus lower extremity compression only. During phase 1, 20 adolescents with POTS will
undergo up to 10 minutes of tilt without compression (trial #1), a repeat study of up to 10
minutes with full compression (trial #2), and a third study without compression up to 10
minutes (trial #3). Compression will be performed using the non-inflatable Zoex anti-shock
garment. During study phase 2, an additional 20 adolescent POTS patients will undergo up to
10 minutes of tilt without compression (trial #1), a repeat study of up to 10 minutes with
abdominal compression only [n=10] or lower extremity compression only [n=10] (trial #2), and
a third study repeated without compression up to 10 minutes (trial #3). To limit compression
to the abdomen only, we will use the Zoex garment strap numbers 4 and 5 (thigh and abdomen)
without straps 1-3 (lower extremities). For lower extremity-only compression, we will use
Zoex garment straps 1-4 (lower extremity and thigh) without strap 5. Data collected will
include mean and peak heart rates and timing of symptoms with each trial. A paired-samples
t-test will be used to compare mean heart rates between trials for each study phase. Hazard
analyses will be used to assess time-based endpoints.