Adolescent Cardiology

Fainting (Syncope) & POTS in Teenagers

Specialist evaluation for dizzy spells, blackouts, and Postural Orthostatic Tachycardia Syndrome (POTS) by consultant paediatric cardiologist Dr Nitha Naqvi at 77 Wimpole Street, London.

What causes fainting and POTS in teenagers?

Fainting in teenagers is predominantly caused by vasovagal syncope, a reflex drop in blood pressure and heart rate triggered by prolonged standing, heat, or dehydration. Postural Orthostatic Tachycardia Syndrome (POTS) is an autonomic condition where standing causes an abnormal heart rate surge (>30–40 bpm) without a blood pressure drop, leading to dizziness, palpitations (SVT/fast pulse), and profound fatigue.

Adolescent syncope evaluation

Recognising Warning Symptoms

Most teenagers experience clear "presyncopal" warning signs before a simple vasovagal faint:

  • Feeling suddenly hot, dizzy, or light-headed
  • Tunnel vision, blurred vision, or "black spots"
  • Ringing in the ears (tinnitus) or muffled hearing
  • Pale skin and sudden cold clamminess

POTS vs Vasovagal Fainting

While simple vasovagal faints occur periodically under specific conditions (e.g. standing in warm assemblies, blood tests), POTS causes chronic, daily postural symptoms:

Feature Vasovagal Syncope (Simple Faint) POTS (Postural Tachycardia)
Heart Rate Normal or slows down during faint Surges by 30–40+ bpm on standing
Blood Pressure Drops suddenly, causing collapse Generally maintained (no large drop)
Frequency Occasional / situational Daily postural dizziness and fatigue

Cardiology Investigations

To differentiate simple syncope from cardiac arrhythmias or autonomic dysfunction, Dr Naqvi provides:

  • Paediatric Echocardiogram: Ruling out structural heart muscle and valve disease.
  • ECG & 24-Hour Rhythm Recording: Checking for conduction delays or rhythm anomalies.
  • Tilt Table Testing & Active Stand Test: Controlled postural monitoring of heart rate and blood pressure changes.

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Frequently Asked Questions: Teenager Fainting & POTS

Expert advice from consultant paediatric cardiologist Dr Nitha Naqvi

Most fainting in teenagers is vasovagal syncope, where blood pools in the legs, briefly lowering blood pressure and cerebral perfusion. Postural Orthostatic Tachycardia Syndrome (POTS) involves autonomic dysregulation causing a sustained heart rate jump of 30–40+ bpm upon standing, accompanied by dizziness, fatigue, and brain fog.

Fainting that occurs during active physical exercise (e.g. while running or swimming), fainting with zero warning symptoms, or blackouts associated with chest pain, palpitations, or a family history of sudden death require immediate specialist evaluation.

Treatment starts with high hydration (2.5–3 litres daily), increased dietary salt, graded recumbent exercise (e.g. rowing, recumbent bike, swimming), and compression leggings. When necessary, medications such as beta-blockers, ivabradine, or midodrine may be prescribed.

Yes. The long-term prognosis is excellent. The majority of adolescents outgrow vasovagal syncope and POTS as their autonomic nervous system stabilizes into adulthood.