CCRN Cardiac Rhythm Interpretation and Management 2 — Questions and Answers
Question 1: A hemodynamically stable patient develops sustained monomorphic ventricular tachycardia with a palpable pulse. What is the preferred first-line pharmacological intervention?
- Atropine 0.5 mg IV push
- Adenosine 6 mg rapid IV push
- Amiodarone 150 mg IV over 10 minutes (Correct answer)
- Digoxin 0.5 mg IV
Correct answer: Amiodarone 150 mg IV over 10 minutes
Amiodarone 150 mg IV over 10 minutes is the first-line antiarrhythmic for stable monomorphic VT when the patient is not in cardiac arrest.
Question 2: A patient in pulseless ventricular fibrillation is identified on the monitor. What is the immediate priority intervention?
- Administer epinephrine 1 mg IV first
- Deliver unsynchronized defibrillation (Correct answer)
- Perform 2 minutes of CPR before shocking
- Deliver synchronized cardioversion at 200 joules
Correct answer: Deliver unsynchronized defibrillation
Unsynchronized defibrillation is the definitive treatment for VF and should be delivered as soon as the rhythm is identified; CPR is resumed immediately after the shock.
Question 3: Atropine 0.5 mg IV is the appropriate initial treatment for which dysrhythmia?
- Ventricular fibrillation
- Symptomatic sinus bradycardia (Correct answer)
- Atrial fibrillation with rapid ventricular response
- Second-degree Mobitz type II AV block
Correct answer: Symptomatic sinus bradycardia
Atropine blocks vagal tone and increases heart rate, making it first-line for symptomatic sinus bradycardia; Mobitz II typically requires pacing, not atropine.
Question 4: A patient presents with paroxysmal supraventricular tachycardia (PSVT) at 180 bpm. Vagal maneuvers have failed. What is the first pharmacological treatment of choice?
- Amiodarone 150 mg IV over 10 minutes
- Synchronized cardioversion at 50 joules
- Verapamil 5 mg IV over 2 minutes
- Adenosine 6 mg rapid IV push followed by a 20 mL saline flush (Correct answer)
Correct answer: Adenosine 6 mg rapid IV push followed by a 20 mL saline flush
Adenosine 6 mg rapid IV push with a saline flush is the first-line drug for PSVT; it briefly blocks AV conduction to terminate reentrant circuits.
Question 5: A hemodynamically stable patient with atrial flutter and a ventricular rate of 150 bpm has no history of prior episodes. What is the most appropriate initial management?
- Immediate unsynchronized defibrillation at 200 joules
- Temporary transvenous pacemaker insertion
- Rate control with a beta-blocker or calcium channel blocker (Correct answer)
- Magnesium sulfate 2 g IV over 10 minutes
Correct answer: Rate control with a beta-blocker or calcium channel blocker
For hemodynamically stable atrial flutter, rate control with a beta-blocker (e.g., metoprolol) or non-dihydropyridine calcium channel blocker (e.g., diltiazem) is the initial priority.
Question 6: A patient in the ICU develops torsades de pointes (polymorphic VT associated with a prolonged QT). Which treatment is most appropriate?
- Amiodarone 150 mg IV bolus
- Magnesium sulfate 1–2 g IV over 5–10 minutes (Correct answer)
- Lidocaine 1 mg/kg IV push
- Adenosine 12 mg rapid IV push
Correct answer: Magnesium sulfate 1–2 g IV over 5–10 minutes
Magnesium sulfate 1–2 g IV is the treatment of choice for torsades de pointes because it stabilizes the cardiac membrane and shortens the QT interval.
Question 7: When performing synchronized cardioversion for hemodynamically unstable atrial fibrillation using a biphasic defibrillator, what is the recommended initial energy setting?
- 10–50 joules
- 50–100 joules
- 120–200 joules (Correct answer)
- 300–360 joules
Correct answer: 120–200 joules
ACLS guidelines recommend 120–200 joules (biphasic, manufacturer-recommended) as the initial energy for cardioversion of atrial fibrillation.
CCRN Cardiac Rhythm Interpretation and Management 2
A hemodynamically stable patient develops sustained monomorphic ventricular tachycardia with a palpable pulse.
What is the preferred first-line pharmacological intervention?