Syncope - Differential Diagnosis

The percentage of syncopal events secondary to arrhythmias or structural disease is generally less than 25%.



Neurally-mediated 66%

 • Vasovagal

 • Carotid sinus

 • Situational

    - Cough

    - Micturition

    - Defaecation

    - Swallow

    - Others

Orthostatic hypotension (10%)

 • Drug induced

 • ANS failure (primary, secondary)

 • Volume depletion

Cardiac arrhythmia - 11%

 • Brady (Sick sinus, AV block)

 • Tachy (VT, SVT)

 • Inherited

Structural cardiopulmonary

 • Aortic stenosis

 • HOCM

 • Pulmonary hypertension

 • Others





Non-syncopal - 6%

 • Metabolic

 • Epilepsy

 • Intoxications

 • Drop-attacks

 • Psychogenic

 • TIA

 • Falls

Unknown - 2%



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