Syncope

Etiology

Cardiac

• Arrhythmia (ventricular tachycardia, supraventricular tachycardia, sick sinus syndrome, sinus bradycardia, sinus arrest, atrioventricular block)
• Aortic stenosis
• Myocardial infarction
• Hypertrophic obstructive cardiomyopathy (HOCM)
• Pulmonary hypertension, pulmonary embolism, pulmonary stenosis
• Atrial myxoma

• Orthostatic or postural hypotension
  • Hypovolemia
  • Drugs, eg, beta-blockers, calcium channel blockers, vasodilators, diuretics
  • Autonomic insufficiency, eg, diabetes, adrenal insufficiency, spinal cord lesion, Guillain-Barré syndrome, chronic idiopathic orthostatic hypotension
• Situational, eg, micturition, defecation, cough, swallow
• Carotid sinus hypersensitivity