Health knowledge made personal
Join this community!
› Share page:
Go
Search posts:

What is the “neural circuit ” in neuro-cardiogenic syncope ?

Posted Aug 17 2010 10:37am

The commonest cause of syncope is the neuro-cardiogenic or vasovagal syncope .

The following is  the possible neural  circuit  of this syncope . In fact . it is a  ”Neuro -vascular circuit”

The afferent* (Two components  are present  -Both trigger sympathetic signal )

  1. Sympathetic (Prodrome /Anxiety /fear )
  2. Cardiac mechano /stetch receptors  located mainly in LV .(Can be in Aorta/Carotid )

* In some cases sensors  and afferent can be same entities.

The centre – Medullary Nucleus ambiguous /Tractus solitarius

The efferent -Strong parasympathetic overshoot and sympathetic withdrawal

Parasympathetic excess lead to bradycardia primarily, while sympathetic  withdrawal lead to

hypotension

Syncope recovery

As patient recumbent posture ; LV gets filled and  LV mechanoreceptors are passified .

Final message

The exact pathophysiologic basis of this syncope  still  not elucidated.But one thing is clear , the syncope is due to sympatho- parasympatho signal mismatch( and sort of a rivalry reaction)  !In this neural game , heart’s behavior is all the more funny , it initiates the reflex  while  the brain stem  “Boomerangs” it back to heart and vascular system ,  with a vagal onslaught .

To call this  simply as vasovagal  is not proper , that is why neuro -cardiogenic syncope was used.

Ideal terminology  would be  to call it as  cardio -neuro -cardiac syncope   as the cardiac component form the afferent limb as well as the efferent (target organ )

Reference


Post a comment
Write a comment:

Related Searches