| Reflex-mediated* |
- Vasovagal
- Orthostatic vasovagal syncope: usually after prolonged standing, frequently in a warm environment, etc
- Emotional vasovagal syncope: secondary to fear, pain, medical procedure, etc
- Unknown trigger
|
- Situational
- Micturition, defecation
- Swallowing
- Coughing/sneezing
|
| |
| Orthostatic hypotension* |
- Medication-related
- Diuretics (eg, thiazide or loop diuretics)
- Vasodilators (eg, dihydropyridine calcium channel blockers, nitrates, alpha blockers, etc)
- Antidepressants (eg, tricyclic drugs, SSRIs, etc)
|
- Volume depletion
- Hemorrhage
- Gastrointestinal losses (ie, vomiting or diarrhea)
- Diminished thirst drive (primarily in older patients)
|
- Autonomic failure
- Primary: pure autonomic failure, Parkinson disease, multiple system atrophy, Lewy body dementia
- Secondary: diabetes mellitus, amyloidosis, spinal cord injuries, autoimmune neuropathy (eg, Guillain-Barré), paraneoplastic neuropathy
|
| Cardiac |
- Tachyarrhythmias
- Ventricular tachycardia
- Supraventricular tachycardias
|
- Bradyarrhythmias (with inadequate ventricular response)
- Sinus node dysfunction
- Atrioventricular block
|
- Structural disease
- Severe aortic stenosis
- Hypertrophic cardiomyopathy
- Cardiac tamponade
- Prosthetic valve dysfunction
- Congenital coronary anomalies
- Cardiac masses and tumors (eg, atrial myxoma)
|
- Cardiopulmonary/vascular
- Pulmonary embolus
- Severe pulmonary hypertension
- Aortic dissection
|
