ECG Question #20


A client is having preoperative tests for a pending cholecystectomy. The preoperative electrocardiogram (ECG) reveals sinus bradycardia, heart rate of 55 bpm, and a PR interval of 0.26 second as indicated on the ECG below:

The rhythm confirms the finding of:


  1. First degree heart block
    • Rationale:
  2. Mobitz type II heart block
    • Rationale:
  3. Wandering pacemaker
    • Rationale:
  4. Second degree AV block
    • Rationale:



First degree AV block is usually asymptomatic and is a common conduction disturbance. The PR interval exceeds 0.20 in first degree heart block (normal PR interval is 0.12 – 0.20 second). It may occur as a result of medications, athletics, and is common among the elderly population. The nurse will inform the physician of the results. The rhythm strip does not indicate Mobitz type II heart block, a wandering pacemaker, or second degree AV block.

Learning Outcomes

Test Taking Tip

Video Rationale