Impaired Endothelial Function in Patients With Postural Tachycardia Syndrome

Abstract

The purpose of this study is to evaluate endothelial function in postural tachycardia syndrome (PoTS), a poorly understood chronic condition characterized by a state of consistent orthostatic tachycardia (delta heart rate ≥30 beats per minute) upon standing without orthostatic hypotension. Nineteen patients with PoTS and 9 healthy controls were studied after 3 days of a fixed, caffeine-free, normal sodium (150 milliequivalents/day) diet. All participants underwent autonomic function testing, including sinus arrhythmia, valsalva maneuver, hyperventilation, cold pressor, handgrip, and a standing test with catecholamine measurements, followed by endothelial function testing. We analyzed 3 measures of endothelial function: percent brachial flow-mediated dilation, digital pulsatile arterial tonometry, and postischemic percent leg blood flow. Flow-mediated dilation was significantly lower in patients with PoTS (6.23±3.54% for PoTS) than in healthy controls (10.6±4.37% for controls versus, P =0.014). PoTS and controls had similar digital pulsatile arterial tonometry (1.93±0.40 arbitrary units for controls versus 2.13±0.63 arbitrary units for PoTS). PoTS had similar but suggestive percent leg blood flow to controls (313±158% for PoTS versus 468±236% for controls, P =0.098). Patients with PoTS have significantly reduced flow-mediated dilation compared with healthy controls, suggesting that PoTS is characterized by endothelial dysfunction in conduit arteries. REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01308099.

SARS-CoV-2 infection causes prolonged cardiomyocyte swelling and inhibition of HIF1α translocation in an animal model COVID-19

“…Patients develop PoTS months after their SARS-CoV-2 infection, without a prior history. Recently, a link with endothelial dysfunction has been made ( 54 ). PoTS patients are reported to have reduced flow-mediated dilations compared to healthy controls ( 54 ).…”

“…Recently, a link with endothelial dysfunction has been made ( 54 ). PoTS patients are reported to have reduced flow-mediated dilations compared to healthy controls ( 54 ). In our hamster model, SARS-CoV-2 infection reduces pericyte coverage and impairs their function in vitro .…”

Worsening Postural Tachycardia Syndrome Is Associated With Increased Glucose-Dependent Insulinotropic Polypeptide Secretion

“…For example, removal of excessive sympathetic activation in obese subjects with the ganglionic blocker, trimethaphan resulted in an improvement in insulin sensitivity during hyperinsulinemic-euglycemic clamps. 24 Alternatively, endothelial dysfunction 25 and sub-clinical inflammation, 26 conditions associated with dysmetabolic states such as insulin resistance and type 2 diabetes, have been described in POTS and could contribute to its pathogenesis.…”

Management of Long-COVID Postural Orthostatic Tachycardia Syndrome With Enhanced External Counterpulsation

“…Based on a study by Chopoorian et al, patients with POTS had reduced flow-mediated dilation when compared to healthy controls, suggesting that POTS is characterized by underlying endothelial dysfunction [ 9 ]. Interestingly, EECP has demonstrated beneficial effects on peripheral artery flow-mediated dilation and endothelial-derived vasoactive agents in patients with symptomatic coronary artery disease [ 10 ].…”