Free Cardioversion & Pacing Practice Questions

1. During transcutaneous pacing of a patient with third-degree heart block, you observe electrical capture on the monitor (pacing spikes followed by wide QRS complexes at 70 bpm). However, the patient remains hypotensive with no palpable pulse synchronous with the paced complexes. This situation is called:

• Failure to achieve mechanical capture — the heart is electrically depolarizing but not contracting effectively
• Failure to sense
• Successful pacing — no further intervention is needed
• Failure to pace

2. A patient with an implanted cardioverter-defibrillator (ICD) is receiving repeated shocks (visible muscle jerking). The patient is conscious, in distress, and the monitor shows sinus tachycardia at 110 bpm. What is the MOST likely problem and the appropriate prehospital intervention?

• The ICD is inappropriately firing on sinus tachycardia — place a magnet over the device to inhibit shock therapy and transport
• The ICD is correctly treating recurrent VT — do not interfere with the device
• Defibrillate the patient externally to override the ICD
• Remove the ICD leads by pulling on the visible portion

3. You are preparing to cardiovert a patient with stable monomorphic VT. After sedation with midazolam, you engage sync mode and charge to 100 joules. You notice the sync markers are falling on the T waves instead of the R waves. What should you do?

• Change the monitoring lead or adjust the ECG gain until the sync markers correctly identify the R waves
• Proceed with cardioversion regardless of marker placement
• Switch to defibrillation mode and shock without synchronization
• Cancel the cardioversion and treat with amiodarone only

4. A patient is being successfully transcutaneously paced at 70 bpm and 80 mA. You confirm mechanical capture with a palpable pulse and improving mental status. To optimize the settings, what adjustment should you make?

• Slowly decrease the mA until capture is lost, then increase by 10% above that threshold to ensure consistent capture with minimal current
• Increase the mA to the maximum setting for safety
• Increase the rate to 120 bpm to ensure overdrive pacing
• Decrease the mA to the lowest possible setting regardless of capture

5. A patient with Torsades de Pointes (polymorphic VT with prolonged QT) deteriorates into a pulseless state. You defibrillate with ROSC achieved. To prevent recurrence of Torsades, what is the recommended pharmacological treatment?

• Magnesium sulfate 1-2 g IV over 15 minutes; consider overdrive pacing if Torsades recurs
• Amiodarone 300 mg IV bolus
• Procainamide 20 mg/min IV infusion
• Lidocaine 1 mg/kg IV bolus