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Dynamic cerebral autoregulation is preserved in neurally mediated syncope.
R Schondorf1, R Stein, R Roberts
1Autonomic Reflex Laboratory, Department of Neurology, McGill University, Montreal, Quebec, Canada H3T 1E2. ronald.schondorf@mcgill.ca
Journal of Applied Physiology (Bethesda, Md. : 1985)
|November 22, 2001
Summary
Cerebral autoregulation is not impaired in patients with neurally mediated syncope (NMS). Dynamic and static cerebral autoregulation functions similarly in NMS patients and healthy individuals during head-up tilt tests.
Area of Science:
- Neurology
- Cardiology
- Physiology
Background:
- Neurally mediated syncope (NMS) is a common condition characterized by transient loss of consciousness.
- Cerebral autoregulation, the brain's ability to maintain stable blood flow, is crucial for neurological function.
Purpose of the Study:
- To investigate whether cerebral autoregulation is impaired in patients experiencing recurrent NMS.
- To compare static and dynamic cerebral autoregulation between NMS patients and healthy controls.
Main Methods:
- Evaluated 37 NMS patients and 15 healthy controls.
- Measured blood pressure (BP), heart rate, and cerebral blood velocity (CBV) using transcranial Doppler.
- Assessed static and dynamic cerebral autoregulation during rest and 80-degree head-up tilt (HUT).
Main Results:
- Static cerebral autoregulation did not differ between NMS patients and controls during HUT.
- Dynamic cerebral autoregulation, assessed via transfer gain, coherence, and phase, remained similar in both groups.
- Cerebral autoregulation was unaffected by the severity of orthostatic intolerance in NMS patients.
Conclusions:
- Cerebral autoregulation is not impaired in patients with recurrent NMS.
- The findings suggest that NMS is not caused by a deficit in cerebral autoregulation mechanisms.