Clinical scenario : Shock | Ventricular tachycardia | Management
12-year-old boy with dilated cardiomyopathy suddenly develops palpitations and collapses. On arrival, he is confused and pale. His heart rate is 220/min, blood pressure is 68/40 mmHg, peripheral pulses are weak, and capillary refill time is 5 seconds. Oxygen saturation is 95% on supplemental oxygen. ECG demonstrates monomorphic ventricular tachycardia. A central pulse is palpable.
What is the most appropriate immediate management?
A. Intravenous amiodarone
B. Intravenous adenosine
C. Intravenous lidocaine
D. Synchronized electrical cardioversion
E. Unsynchronized defibrillation
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Correct Answer: D. Synchronized electrical cardioversion
Explanation; Synchronized electric cardioversion
This child has unstable ventricular tachycardia with a pulse.
The diagnosis is supported by:
- Regular wide-complex tachycardia
- Palpable pulse
- Hypotension
- Poor peripheral perfusion
- Altered hemodynamic status
According to the PALS tachycardia algorithm, any child with ventricular tachycardia and signs of hemodynamic instability (hypotension, shock, altered mental status, ischemic chest pain, or heart failure) requires immediate synchronized electrical cardioversion.
The recommended initial synchronized cardioversion dose is:
- 0.5–1 J/kg
- If unsuccessful, increase to 2 J/kg
Sedation should be provided only if it does not delay cardioversion.
Why the other options are incorrect
A. Intravenous adenosine
Adenosine is used for stable regular narrow-complex supraventricular tachycardia and may be considered only if a regular monomorphic wide-complex tachycardia is thought to be SVT with aberrancy. It is not appropriate for an unstable child with presumed ventricular tachycardia.
B. Intravenous amiodarone
Amiodarone is used for stable monomorphic ventricular tachycardia or after expert consultation. It should not delay immediate synchronized cardioversion in an unstable patient.
C. Intravenous lidocaine
Lidocaine is an alternative antiarrhythmic for selected stable ventricular arrhythmias but is not first-line in unstable ventricular tachycardia.
D. Synchronized electrical cardioversion
Correct. Hemodynamic instability with a pulse is an indication for immediate synchronized cardioversion.
E. Unsynchronized defibrillation
Defibrillation is indicated for pulseless ventricular tachycardia or ventricular fibrillation, not for ventricular tachycardia with a pulse.
Learning Point
The management of ventricular tachycardia depends on whether a pulse is present and whether the patient is stable:
- Stable VT with a pulse: Consider antiarrhythmic therapy (e.g., amiodarone or procainamide with expert guidance).
- Unstable VT with a pulse: Immediate synchronized cardioversion (0.5–1 J/kg, increasing to 2 J/kg if needed).
- Pulseless VT: Immediate unsynchronized defibrillation and full pediatric cardiac arrest protocol.
