DC Dysrhythmia Patient Care & Safety Standards 3 — Questions and Answers
Question 1: During cardiac monitoring, a nurse observes P waves with no consistent relationship to QRS complexes and independent atrial and ventricular rates. Which rhythm is present?
- Second-degree AV block Type II (Mobitz II)
- Junctional escape rhythm
- Third-degree (complete) heart block (Correct answer)
- Accelerated idioventricular rhythm
Correct answer: Third-degree (complete) heart block
Third-degree heart block is characterized by complete dissociation between atrial and ventricular activity, with each beating independently.
Question 2: A patient with a permanent pacemaker set at 60 bpm shows a heart rate of 58 bpm with no visible pacer spikes. What is the most appropriate nursing action?
- Reassure the patient that this is within normal limits
- Apply a magnet over the pacemaker generator
- Assess the patient, check connections, and notify the provider (Correct answer)
- Increase the sensitivity on the cardiac monitor
Correct answer: Assess the patient, check connections, and notify the provider
Failure to pace below the programmed rate requires immediate patient assessment and provider notification to evaluate for pacemaker malfunction.
Question 3: A patient converted from atrial fibrillation to sinus rhythm. Which complication requires priority assessment in the first 24–48 hours post-cardioversion?
- Hypervolemia from cardioversion energy delivery
- Thromboembolism or stroke (Correct answer)
- Development of sinus tachycardia
- Hypercalcemia from electrode use
Correct answer: Thromboembolism or stroke
Cardioversion can dislodge atrial thrombi formed during AF, putting the patient at high risk for thromboembolic events including stroke.
Question 4: Which electrolyte imbalance most directly prolongs the QT interval and predisposes a patient to life-threatening ventricular dysrhythmias?
- Hypernatremia
- Hypomagnesemia (Correct answer)
- Hyperchloremia
- Hyperphosphatemia
Correct answer: Hypomagnesemia
Hypomagnesemia prolongs the QT interval and is a major risk factor for torsades de pointes and other ventricular dysrhythmias.
Question 5: A patient in pulseless ventricular fibrillation has been defibrillated once and CPR resumed. After 2 minutes of CPR, the rhythm is still VF. What is the next step?
- Administer lidocaine 1.5 mg/kg IV and continue CPR for 5 minutes
- Defibrillate again and administer epinephrine 1 mg IV (Correct answer)
- Check pulse for 30 seconds before delivering another shock
- Switch to synchronized cardioversion at 150J
Correct answer: Defibrillate again and administer epinephrine 1 mg IV
Per ACLS protocol, after the second defibrillation attempt for refractory VF, epinephrine 1 mg IV is given every 3–5 minutes and defibrillation is repeated.
Question 6: Which lead placement is most useful for identifying P wave morphology and differentiating supraventricular from ventricular rhythms?
- Lead I
- Lead aVR
- Lead II or MCL1 (V1 equivalent) (Correct answer)
- Lead aVL
Correct answer: Lead II or MCL1 (V1 equivalent)
Lead II provides the best visualization of P waves along their normal vector, while MCL1/V1 helps differentiate SVT with aberrancy from VT.
Question 7: A patient on the telemetry floor is found unresponsive. The monitor shows a flat line. What should the nurse do first?
- Begin chest compressions immediately
- Increase the gain on the cardiac monitor
- Check lead connections and verify rhythm in a second lead (Correct answer)
- Call a code blue and prepare for defibrillation
Correct answer: Check lead connections and verify rhythm in a second lead
A flat line may represent asystole or a loose lead; verifying electrode connections and checking another lead prevents unnecessary interventions.
DC Dysrhythmia Patient Care & Safety Standards 3
During cardiac monitoring, a nurse observes P waves with no consistent relationship to QRS complexes and independent atrial and ventricular rates.
Which rhythm is present?