Cause of syncopes

Reflex (neurological mediation)

• vasovagal
• carotid sinus hypersensitivity
• situational (cough, gasto-intestinal stimulation, micturion, postprandial, post-effort)

Orthostatic

• primary dysfunction of the autonomic nervous system: Parkinson disease, dementia.
• secondary dysfunction of the autonomic nervous system: diabetes, amyloïdosis, uremia, vertebral trauma.
• iatrogenic orthostatic hypotension: alcool, vasodilators, diuretics, antidepressive drugs.
• volume depletion.

Cardiovascular

• bradycardia (sick sinus syndrome, AV block, pacemaker dysfunction)
• tachycardia (supra-ventricular, ventricular)
• iatrogenic following drug administration (torsades de pointes)
• structural (obstructive cardiomyopathy, aortic stenosis, cardiac tumor, tamponnade, etc...)
• pulmonary embolism, aortic dissection.