Table 6.

Classification of supraventricular tachyarrhythmias. Adapted from the Paediatric Critical Care Study Guide and the Advanced Paediatric Life Support treatment guidelines^5,17,¹⁸

1.Re-entry SVT			Unstable 1. Cardioversion 1–2 J kg−1 Stable 1. Vagal manoeuvre 2. Adenosine Incremental dosing every 2 min •0.1 mg kg−1 •0.2 mg kg−1 • 0.3 mg kg−1 ∗ Therapeutic in AVRT and AVNRT ∗ Diagnostic in atrial re-entry 3.Consider: • Adenosine 0.4 mg–0.5 mg kg−1 ∗ Maximum: 12 mg ∗ Neonate: 0.3 mg kg−1 •Amiodarone 5 mg kg−1 over 30 min •Cardioversion
○Atrial re-entry
•Atrial fibrillation	•Absent P waves •Oscillating baseline/fibrillation waves •Irregular ventricular rhythm •Normal QRS duration
•Atrial flutter	•Sawtooth P waves •Regular ventricular rhythm •Ventricular rate usually 150 min−1 with a 2:1 AV block •Normal QRS duration
○AVRT	•Retrograde P waves midway between two QRS complexes
•Orthodromic SVT	•Normal QRS duration
•Antidromic SVT	•Prolonged QRS duration
•Wolf–Parkinson–White	•Can give rise to either an orthodromic (narrow complex QRS) or antidromic (wide complex QRS) SVT •Sinus rhythm ECG features: short PR, delta wave and widened QRS
○AVNRT	•Retrograde P waves shortly after QRS or buried within QRS •Normal QRS duration
2.Automatic SVT
•Sinus tachycardia	•One P wave before every QRS •Normal P-wave morphology •Normal P-wave axis •Regular ventricular rhythm •Gradual onset •Rate less than age-appropriate max •Normal QRS duration		Treat underlying cause
•Ectopic atrial tachycardia	•Abnormal P-wave morphology •Usually regular ventricular rhythm •Normal QRS duration		Slow automaticity 1.Correct electrolyte abnormalities 2.Correct hypoxia 3.Correct acidosis 4.Correct hypovolaemia 5.Correct anaemia 6.Decrease inotropes if possible 7.Induce mild hypothermia 8.Sedate 9.Dexmedetomidine∗ 10.Amiodarone Restore AV synchrony 1.Overdrive pacing
•Multifocal atrial tachycardia	•Three or more P-wave morphologies •Variable PR and RR intervals •Normal QRS duration
•JET	•Retrograde P waves •Regular ventricular rhythm •Variable AV conduction •Gradual rate increase •Central venous pressure waveform displays cannon waves •Normal QRS duration

^∗Kadam and colleagues.¹⁸