Syncope (Fainting)

Syncope (fainting) is a brief loss of consciousness due to a temporary reduction in blood flow to the brain. Most causes are benign (vasovagal), but some can be cardiac and dangerous.

Table of Contents

Quick Facts

  • ICD-10: R55

Concerning Features

Seek urgent care for syncope with:
  • Chest pain or palpitations before the event
  • Occurs during exertion or while lying down
  • No warning symptoms
  • Injury from fall
  • Family history of sudden cardiac death
  • Known heart disease

Common Causes

  • Vasovagal (most common) — pain, fear, prolonged standing
  • Orthostatic hypotension
  • Dehydration, low blood sugar
  • Cardiac arrhythmia
  • Structural heart disease (aortic stenosis)
  • Medications
  • Pulmonary embolism

Evaluation

  • Detailed history and physical
  • ECG
  • Orthostatic vital signs
  • Blood tests as indicated
  • Echocardiogram, tilt-table testing, Holter monitor in selected patients

Related Conditions

Hypotension

Common cause

 Bradycardia

Possible cause

 Long QT Syndrome

Cardiac cause
Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. If you are experiencing a medical emergency, call your local emergency number immediately.

References

  • AHA/ACC/HRS. Syncope Guideline.