Supraventricular Tachycardia

Key points

• Paroxysmal SVT: sudden-onset narrow-complex tachycardia, typically AVNRT; also AVRT and junctional tachycardias.
• Acute: vagal manoeuvres (Valsalva) → IV adenosine 6 mg → 12 mg → 12 mg.
• Adenosine contraindicated in asthmatics — verapamil preferable.
• Electrical cardioversion if unstable. Prevention: beta-blockers · radio-frequency ablation.

Decision points in this pathway

• Haemodynamically unstable?
• Terminates?

The full step-by-step algorithm, including what to do at each branch, opens in the app for approved members.