ACLS Tachycardia and Bradycardia Algorithms 4 — Questions and Answers
Question 1: A patient has a third-degree (complete) heart block with a ventricular rate of 35 bpm and BP of 70/40. What is the most appropriate immediate intervention?
- Atropine 0.5 mg IV and prepare for transcutaneous pacing (Correct answer)
- Adenosine 6 mg IV push
- Amiodarone 150 mg IV over 10 minutes
- Defibrillation at 200 J
Correct answer: Atropine 0.5 mg IV and prepare for transcutaneous pacing
Symptomatic complete heart block requires atropine as a temporizing measure while preparing for transcutaneous pacing.
Question 2: During treatment of stable monomorphic VT, amiodarone is selected. What is the correct dosing?
- 150 mg IV over 10 minutes, then 1 mg/min for 6 hours (Correct answer)
- 300 mg IV push followed by 150 mg in 3–5 minutes
- 1 mg/min continuous infusion only
- 500 mg oral loading dose
Correct answer: 150 mg IV over 10 minutes, then 1 mg/min for 6 hours
For stable monomorphic VT, amiodarone is given as 150 mg IV over 10 minutes followed by a 1 mg/min maintenance infusion.
Question 3: Which of the following rhythms is most likely to be converted by vagal maneuvers?
- Atrial fibrillation
- Atrial flutter
- AV nodal reentrant tachycardia (AVNRT) (Correct answer)
- Ventricular tachycardia
Correct answer: AV nodal reentrant tachycardia (AVNRT)
AVNRT depends on the AV node as part of its reentrant circuit and can be terminated by vagal maneuvers that slow AV conduction.
Question 4: A patient in unstable tachycardia is being prepared for synchronized cardioversion. The defibrillator is not synchronizing properly. What should the provider do?
- Delay cardioversion and call for another defibrillator
- Proceed with unsynchronized shock at maximum energy (Correct answer)
- Administer adenosine while troubleshooting
- Apply external pacing instead
Correct answer: Proceed with unsynchronized shock at maximum energy
If synchronization fails and the patient is critically unstable (near pulseless), proceed with an unsynchronized shock to prevent delay in treatment.
Question 5: Which finding on ECG is most consistent with supraventricular tachycardia (SVT) rather than ventricular tachycardia?
- AV dissociation
- Positive concordance in precordial leads
- Narrow QRS complex (< 120 ms) (Correct answer)
- Fusion beats
Correct answer: Narrow QRS complex (< 120 ms)
A narrow QRS complex (< 120 ms) strongly suggests a supraventricular origin of the tachycardia.
Question 6: Epinephrine infusion is used for bradycardia at what dose range in ACLS?
- 0.1–0.5 mcg/kg/min
- 2–10 mcg/min
- 1–10 mcg/min (Correct answer)
- 10–20 mcg/min
Correct answer: 1–10 mcg/min
Epinephrine is infused at 2–10 mcg/min for symptomatic bradycardia as an alternative when atropine is ineffective.
Question 7: A patient converts from SVT to sinus rhythm after adenosine but develops a brief period of asystole lasting 6 seconds. What is the correct response?
- Immediately administer atropine 1 mg IV
- Begin CPR
- Reassure the patient — this is an expected, transient effect of adenosine (Correct answer)
- Perform synchronized cardioversion
Correct answer: Reassure the patient — this is an expected, transient effect of adenosine
Brief asystole after adenosine is expected due to its transient AV nodal blockade and typically resolves spontaneously within seconds.
ACLS Tachycardia and Bradycardia Algorithms 4
A patient has a third-degree (complete) heart block with a ventricular rate of 35 bpm and BP of 70/40.
What is the most appropriate immediate intervention?