PALS Tachycardia With a Pulse 2 — Questions and Answers
Question 1: A 3-year-old presents with a heart rate of 220 bpm, poor perfusion, and altered mental status. The rhythm is narrow-complex and regular. What is the most appropriate next intervention?
- Synchronized cardioversion at 1 J/kg (Correct answer)
- Adenosine 0.1 mg/kg IV
- Amiodarone 5 mg/kg IV
- Defibrillation at 2 J/kg
Correct answer: Synchronized cardioversion at 1 J/kg
Unstable SVT with signs of poor perfusion requires immediate synchronized cardioversion starting at 1 J/kg.
Question 2: Which ECG feature best distinguishes sinus tachycardia from SVT in a pediatric patient?
- P-waves present before every QRS with a normal axis (Correct answer)
- Heart rate above 180 bpm
- Narrow QRS complex
- Regular rhythm
Correct answer: P-waves present before every QRS with a normal axis
Sinus tachycardia shows upright P-waves with a normal axis preceding each QRS, unlike SVT which often shows absent or retrograde P-waves.
Question 3: A 6-year-old with SVT receives adenosine 0.1 mg/kg IV without conversion. What is the next dose of adenosine?
- 0.2 mg/kg IV (Correct answer)
- 0.3 mg/kg IV
- 0.05 mg/kg IV
- Repeat 0.1 mg/kg IV
Correct answer: 0.2 mg/kg IV
If the first dose of adenosine (0.1 mg/kg) fails, the second dose is doubled to 0.2 mg/kg (max 12 mg).
Question 4: In a child with wide-complex tachycardia and a pulse who is hemodynamically stable, which drug is preferred?
- Amiodarone 5 mg/kg IV over 20–60 minutes (Correct answer)
- Adenosine 0.1 mg/kg IV rapid push
- Lidocaine 1 mg/kg IV bolus
- Epinephrine 0.01 mg/kg IV
Correct answer: Amiodarone 5 mg/kg IV over 20–60 minutes
Amiodarone is the preferred antiarrhythmic for stable wide-complex tachycardia in pediatric patients per PALS guidelines.
Question 5: Which scenario is MOST consistent with sinus tachycardia rather than SVT?
- Heart rate that gradually decreases with fluid administration for dehydration (Correct answer)
- Abrupt onset of tachycardia with rate of 240 bpm
- Heart rate that does not vary with vagal maneuvers
- Fixed heart rate unchanged by activity or rest
Correct answer: Heart rate that gradually decreases with fluid administration for dehydration
Sinus tachycardia has an identifiable cause (e.g., fever, dehydration) and responds to treatment of that cause, often showing gradual rate change.
Question 6: When performing synchronized cardioversion for unstable SVT in a child, which energy level is used for the second attempt if the first is unsuccessful?
- 2 J/kg (Correct answer)
- 0.5 J/kg
- 3 J/kg
- 4 J/kg
Correct answer: 2 J/kg
If the initial synchronized cardioversion at 1 J/kg fails, the second attempt uses 2 J/kg.
Question 7: A child with SVT is conscious and has adequate perfusion. IV access is unavailable. What is the most appropriate initial intervention?
- Vagal maneuvers such as ice water to the face (Correct answer)
- Synchronized cardioversion at 1 J/kg
- Intraosseous adenosine 0.1 mg/kg
- Amiodarone infusion via peripheral IV
Correct answer: Vagal maneuvers such as ice water to the face
In stable SVT without IV access, vagal maneuvers (e.g., ice water facial immersion in infants) are the first-line intervention.
PALS Tachycardia With a Pulse 2
A 3-year-old presents with a heart rate of 220 bpm, poor perfusion, and altered mental status.
The rhythm is narrow-complex and regular.
What is the most appropriate next intervention?