Pathophysiology
Syncope results from a temporary reduction in cerebral perfusion. Although in a significant proportion of cases (up to 50%) no underlying pathology is identified, there are a number of recognised causes of syncope:
| Classification of Syncope | ||
|---|---|---|
| Neurally mediated syncope | vasovagal (common faint), carotid sinus syncope, Situational e.g. cough, sneeze, GI stimulation, micturition, post prandial | |
| Orthostatic | Drug effects Volume depletion Autonomic failure – e.g. Parkinsons disease, diabetic neuropathy | |
| Cardiac arrythmias | e.g. SVT, VT, Inhereted syndromes (long / short QT, Brugada, WPW) | |
| Structural cardiac disease | Ventricular failure Aortic stenosis HOCM | |
| Cerebrovascular | Vascular steal | |
We will look at each of these on the next page.