Cardiovagal Baroreflex Deficits Impair Neurovascular Coupling and Cognition in POTS
Status:
Active, not recruiting
Trial end date:
2022-06-01
Target enrollment:
Participant gender:
Summary
Postural tachycardia syndrome (POTS), is the chronic form of orthostatic intolerance
associated with excessive upright tachycardia, and occurs predominantly in young females
(>85%). Among its most troubling symptoms are lightheadedness, fatigue, and decreased memory
often called "brain fog" by patients. Task-related neurovascular coupling (NVC) links neural
activity to an increase in CBF known as "functional hyperemia". Although memory task
performance and NVC deteriorated with angle of tilt in POTS but not healthy controls,
cerebral blood flow (CBF) remained similar to control. Instead, the investigators observed
extensive narrow band low frequency (0.07-0.13 Hz) oscillations in BP (OBP) that entrained
and amplified oscillations in CBF (OCBF). OBP and OCBF increased with tilt angle and caused
impaired working memory and reduced functional hyperemia. The cardiovagal baroreflex couples
BP to HR to buffer BP changes. The investigators hypothesize that the cardiovagal baroreflex
becomes progressively impaired with orthostasis in POTS, but not in healthy volunteers, and
accounts for OBP, OCBF, and loss of NVC; further, improving the baroreflex reduces OBP, OCBF
and Brain Fog in POTS.