Lower-body compression best tackles the troublesome heart rate response and symptoms associated with postural orthostatic tachycardia syndrome (POTS), a small study suggests.
POTS affects an estimated 1 million to 3 million Americans, predominantly women, and can dramatically affect quality of life, lead author Kate M. Bourne, BSc, Cumming School of Medicine, University of Calgary, Alberta, Canada, explained in an interview.
Patients experience myriad chronic symptoms but the hallmark, based on consensus criteria, is a sustained heart rate increase of at least 30 beats/minute within 10 minutes of standing without a blood pressure drop of more than 20/10 mm Hg.
Compression garments are thought to work by displacing blood pooled in the abdomen and lower extremities back to the heart to increase preload and reduce heart rate, she said. Evidence to support their effectiveness, however, is lacking, particularly for waist-high garments.
For the study, 30 adults (93% female; age, 32 years) completed 10 minutes of head-up tilt tests (HUT) under four conditions: no compression or a noninflatable compression garment applied to the lower legs, abdomen and thighs, and full lower body. Think compression socks, compression shorts, and waist-high shapewear tights from Spanx.
Heart rate was similar at supine baseline between full and no compression (70 vs 71 beats/minute) but 17 beats/min lower with full compression during HUT (92 vs 109 beats/min; P < .001).
Heart rate increase on HUT fell below POTS criteria with full compression but not without compression (23 vs 39 beats/min; P < .001).
The reduction in orthostatic tachycardia with full compression was driven by better maintenance of stroke volume during HUT (76 vs 63 mL; P < .001), the researchers reported in the January 26 issue of the Journal of the American College of Cardiology.
Full compression also increased systolic blood pressure during supine baseline (121 vs 116 mm Hg; P = .005) and HUT (116 vs 105 mm Hg; P < .001).
There was no difference in cardiac output between full and no compression during testing.
Scores on the 90-point Vanderbilt Orthostatic Symptom Scores (VOSS) scale improved after HUT from an average of 26 with no compression to 12 with full lower-body compression, with higher scores indicating greater symptom burden (P < .001).
A dose-dependent decrease in HUT heart rate was seen across the four compression conditions (none, 109 beats/min; leg, 103 beats/min; abdominal/thigh, 97 beats/min; full, 92 beats/min; P < .001), along with a dose-dependent trend in improved VOSS symptoms.
Lower-leg compression provided minimal improvement in heart rate or symptoms, whereas targeting the abdomen and thigh also lowered the orthostatic heart rate increase on HUT below the POTS diagnostic threshold of 30 beats/min.
“Waist-high tights can be uncomfortable, especially if you live in a warm climate or it’s summer, so wearing an abdominal shapeware garment like Spanx or compression shorts could be less challenging to manage,” Bourne said.
Overall, patients with greater orthostatic tachycardia experienced the most benefit from a compression garment.
In a linked editorial, David G. Benditt, MD, and Richard Sutton, DSc, MBBS, observe that the POTS landscape includes symptoms that, for the most part, are unrelated to posture, such as chronic fatigue, migraine, and a multitude of gastrointestinal disturbances. “As currently used, POTS is no longer ‘fundamentally a condition dependent on gravity,’ as previously suggested.”
Tilt-table testing, however, only addresses a small part of POTS and doesn’t accurately replicate day-to-day activity, note Benditt, from the University of Minnesota Medical School, Minneapolis, and Sutton, from the Imperial College London.
Before relying on heart rate modification as an appropriate treatment end point, the initial step should be to establish a definitive diagnosis by removing potential causes of a POTS-like picture in which symptoms are due to identifiable and treatable causes, the editorialists say.
Constrictive garments for POTS are best considered “transitional therapy used to facilitate initiation of conditioning exercise protocols, which may offer longer-term benefit for both orthostatic and nonorthostatic symptoms,” Benditt and Sutton suggest.
Principal investigator Satish R. Raj, MD, MSCI, chief of the arrhythmia section and medical director of the Autonomic Investigation & Management Centre at the University of Calgary, agreed that further data are needed to determine whether other compression garments will provide the same results or work in the long term.
That said, he noted that there was a “very beautiful correlation” between heart rate reduction and symptom improvement, which in a population often unable to work, attend school, or even grocery shop, can be meaningful.
“Maybe we’re picking up low-hanging fruit; this is a simple therapy that’s cheap, it’s free of any long-term side effects, and relatively free of short-term side effects besides the nuisance of putting these things on,” Raj said. “But the key message is that we can help people.”
“We’re trying to give tools to the average physician who is seeing these patients [because] most of these patients aren’t seen by specialty autonomic centers,” he said.
POTS was most commonly diagnosed by a general cardiologist (41%), followed by a neurologist (19%), electrophysiologist (15%), and family physician (8%).
Notably, participants saw an average of seven physicians prior to their diagnosis, and 75% reported being misdiagnosed.
The study was supported by the Libin Cardiovascular Institute. Bourne is a Vanier Scholar supported by the Canadian Institutes of Health Research. Raj reports consulting for Lundbeck NA and Theravance Biopharma; chairing the data safety and monitoring board for Arena Pharmaceuticals; serving as a network investigator for Cardiac Arrhythmia Network of Canada; and having been a medical advisory board member of Dysautonomia International and PoTS UK, both without financial compensation. Benditt was supported in part by a grant from the Dr Earl E. Bakken family in support of heart-brain research. Sutton reports no relevant relationships.