ACLS Electrical Therapies and Defibrillation 2 — Questions and Answers
Question 1: What is the recommended initial energy for synchronized cardioversion of unstable atrial flutter using a biphasic device?
- 10–20 J
- 50–100 J (Correct answer)
- 120–200 J
- 200–360 J
Correct answer: 50–100 J
Atrial flutter typically responds to lower cardioversion energies; ACLS recommends starting at 50–100 J biphasic for unstable flutter.
Question 2: A patient in pulseless VT is refractory after two defibrillation attempts. What is the recommended next action regarding energy?
- Continue at the same energy level for all subsequent shocks
- Decrease the energy by 50 J with each subsequent attempt
- Use manufacturer-recommended escalating doses or maximum dose for subsequent shocks (Correct answer)
- Switch to synchronized cardioversion for the next attempt
Correct answer: Use manufacturer-recommended escalating doses or maximum dose for subsequent shocks
For refractory VF/pVT, subsequent shocks should use manufacturer-recommended escalating energy or the maximum device dose to improve defibrillation success.
Question 3: Which condition requires immediate unsynchronized defibrillation rather than synchronized cardioversion?
- Atrial fibrillation with rapid ventricular response
- Supraventricular tachycardia with hypotension
- Polymorphic VT (irregular) with a pulse and hemodynamic instability (Correct answer)
- Regular monomorphic VT with a pulse and hypotension
Correct answer: Polymorphic VT (irregular) with a pulse and hemodynamic instability
Polymorphic VT is treated like VF with unsynchronized high-energy shocks because the irregular rhythm makes synchronization difficult and dangerous.
Question 4: During transcutaneous pacing for a patient with symptomatic bradycardia, what initial pacing rate is recommended?
- 40–50 beats per minute
- 60–80 beats per minute (Correct answer)
- 100–120 beats per minute
- 150 beats per minute
Correct answer: 60–80 beats per minute
Transcutaneous pacing is typically initiated at 60–80 beats per minute, which provides adequate cardiac output without causing excessive tachycardia.
Question 5: How is electrical capture confirmed during transcutaneous pacing?
- The patient reports feeling a shock with each pacing spike
- Pacing spikes appear on the ECG at the set rate
- Wide QRS complexes follow each pacing spike AND a pulse is palpable (Correct answer)
- The monitor shows a paced rhythm at the set rate only
Correct answer: Wide QRS complexes follow each pacing spike AND a pulse is palpable
Electrical capture is confirmed by wide QRS complexes following each pacing spike AND mechanical capture by palpating a pulse corresponding to the paced rate.
Question 6: When placing defibrillator pads on a patient with an implanted pacemaker or ICD, how should the pads be positioned?
- Directly over the implanted device for best conduction
- At least 1 inch (2.5 cm) away from the implanted device (Correct answer)
- Only posterior pad placement should be used
- The device must be deactivated before defibrillation
Correct answer: At least 1 inch (2.5 cm) away from the implanted device
Pads should be placed at least 1 inch (2.5 cm) from the implanted device to avoid energy shunting and damage to the device or myocardium.
Question 7: A patient in unstable SVT requires synchronized cardioversion but the device keeps firing randomly. What is the most likely cause?
- The device is malfunctioning and must be replaced
- The synchronize button was not activated before charging
- The ECG lead is detecting artifact instead of R-waves, preventing sync (Correct answer)
- The energy selected is too low for synchronization to occur
Correct answer: The ECG lead is detecting artifact instead of R-waves, preventing sync
If synchronization fails, poor lead contact or artifact may prevent the device from detecting R-waves; checking lead placement and selecting the best ECG lead resolves this.
ACLS Electrical Therapies and Defibrillation 2
What is the recommended initial energy for synchronized cardioversion of unstable atrial flutter using a biphasic device?