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Vasovagal syncope (VVS)

Neurocardiogenic or vasovagal syncope is a clinical manifestation of the vasovagal reflex, characterized by the occurrence of bradycardia and hypotension.

Neurocardiogenic or vasovagal syncope is a clinical manifestation of the vasovagal reflex, characterized by the occurrence of bradycardia and hypotension.

  • M/C form of reflex syncope & syncope overall (⅓ cases)
  • M/C form of syncope in adults

Classification

Syncope:

Transient and self-terminating loss of consciousness (LOC) with rapid onset, short duration combined with spontaneous, prompt and complete recovery.

Reflex syncope:

Syncope resulting from a failure in autoregulation of blood pressure, and ultimately, in cerebral perfusion pressure resulting in transient loss of consciousness.
Classification of syncope | Aydin, M. A., Salukhe, T. V., Wilke, I., & Willems, S. (2010). Management and therapy of vasovagal syncope: A review. World journal of cardiology, 2(10), 308–315. https://doi.org/10.4330/wjc.v2.i10.308

Typical VVS:

Diagnosed when loss of consciousness (LOC) is precipitated by triggers as strong emotion/fear or prolonged standing and is associated to autonomic prodromes (pallor, sweating, nausea, abdominal discomfort)

Non-typical VVS:

Includes episodes of LOC without any evident trigger and without (or only minimal) autonomic prodromes and can be diagnosed when LOC is induced during tilt testing in the absence of other competing diagnosis.

Pathophysiology

Characterized by a reflex activation triggering a rapid decrease in heartbeat and a reduction of vascular tone. Activation of this reflex mechanism provokes bradycardia, vasodilatation and hypotension. The main trigger for this reflex loops is a reduction in venous return during upright position.


Clinical features

Symptom onset during standing, light-headedness and full recovery after a few minutes.

  • Brief loss of consciousness

Symptoms before fainting:

Caused by reduced cerebral perfusion
  • Fatigue, weakness, dizziness, wetness of the skin, dimming of vision, and sometimes tinnitus and complete loss of vision

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