Syncope may be defined as a transient loss of consciousness due to global cerebral hypoperfusion with rapid onset, short duration and spontaneous complete recovery. Note how this definition excludes other causes of collapse such as epilepsy.

Reflex syncope is the most common cause of syncope. There are a number of subtypes:
  • vasovagal: triggered by emotion, pain or stress. Often referred to as 'fainting'. This is the most common cause of syncope and may account for up to 50% of cases of syncope
  • situational: cough, micturition, gastrointestinal
  • carotid sinus syncope


  • Incidence: 1000.00 cases per 100,000 person-years
  • Peak incidence: 70+ years
  • Sex ratio: 1:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features