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Heart

Supraventricular Tachycardia

Sudden episodes of a rapid heartbeat that originates above the heart's lower chambers.

Supraventricular tachycardia (SVT) is a group of arrhythmias causing sudden episodes of rapid heart rate — typically 150–250 bpm. Catheter ablation achieves success rates exceeding 95% for common forms.

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Illustration of the heart's electrical pathways during an episode of supraventricular tachycardia (SVT)

SVT causes sudden bursts of rapid heartbeats due to abnormal electrical pathways, often treated effectively with catheter ablation.

Types of SVT

  • AVNRT (most common, ~60%) — uses dual pathways near the AV node; predominantly affects women
  • AVRT — involves accessory pathway between atria and ventricles; includes Wolff-Parkinson-White (WPW) syndrome
  • Atrial Tachycardia — originates from focal site within atrial muscle; can be incessant and cause cardiomyopathy

Symptoms

  • Sudden-onset rapid, regular palpitations
  • Breathlessness and chest tightness
  • Dizziness and presyncope
  • Neck pulsations (characteristic of AVNRT)
  • Syncope (uncommon, except with WPW complications)

Diagnosis

  • 12-lead ECG during tachycardia
  • Resting ECG (identifies delta wave in WPW)
  • Holter monitoring or event recorder
  • Electrophysiology study (EPS)

Acute Treatment

  • Modified Valsalva manoeuvre
  • Carotid sinus massage
  • Intravenous adenosine
  • Electrical cardioversion for severe cases

Long-Term Treatment

  • Catheter ablation (definitive, first-line for symptomatic patients; >95% success rate)
  • Antiarrhythmic medications: beta-blockers, calcium channel blockers, flecainide

Concerned About Supraventricular Tachycardia?

Dr. Peter Chang offers specialist assessment and personalised management at Paragon Medical Centre, Singapore.