EKG certification Certification EKG Certification Trivia 1 — Questions and Answers
Question 1: What is the normal range for the PR interval on a standard EKG?
- 0.06–0.10 seconds
- 0.12–0.20 seconds (Correct answer)
- 0.22–0.30 seconds
- 0.30–0.40 seconds
Correct answer: 0.12–0.20 seconds
The normal PR interval is 0.12–0.20 seconds (3–5 small squares). A PR interval shorter than 0.12 seconds suggests a pre-excitation syndrome, while one longer than 0.20 seconds indicates first-degree AV block.
Question 2: Which EKG pattern shows progressive lengthening of the PR interval until a QRS complex is dropped?
- First-degree AV block
- Mobitz Type I (Wenckebach) block (Correct answer)
- Mobitz Type II block
- Complete heart block
Correct answer: Mobitz Type I (Wenckebach) block
Mobitz Type I (Wenckebach) is characterized by progressive PR interval lengthening with each beat until one QRS complex is dropped entirely, then the cycle resets. This occurs due to intermittent failure of conduction through the AV node.
Question 3: On a standard EKG tracing run at 25 mm/sec, how many large squares represent 1 second?
- 2 large squares
- 3 large squares
- 5 large squares (Correct answer)
- 10 large squares
Correct answer: 5 large squares
At the standard paper speed of 25 mm/sec, each large square represents 0.20 seconds (5 small squares). Therefore, 5 large squares equal 1 full second. This relationship is fundamental for calculating heart rate.
Question 4: A patient's EKG shows ST-segment elevation of 2 mm in leads II, III, and aVF. Which coronary artery territory is most likely involved?
- Left anterior descending artery
- Left circumflex artery
- Right coronary artery (Correct answer)
- Left main coronary artery
Correct answer: Right coronary artery
ST elevation in leads II, III, and aVF represents an inferior wall STEMI, which is most commonly caused by occlusion of the right coronary artery (RCA). The inferior wall of the left ventricle is predominantly supplied by the RCA in most patients.
Question 5: Which finding on an EKG is most consistent with hyperkalemia?
- Prolonged QT interval
- Tall, peaked T waves (Correct answer)
- Prominent U waves
- Short PR interval
Correct answer: Tall, peaked T waves
Hyperkalemia classically produces tall, narrow, peaked (tent-shaped) T waves, which are often the earliest EKG change. As potassium rises further, the PR interval prolongs, the QRS widens, and eventually a sine-wave pattern may develop.
Question 6: In a patient with sinus bradycardia, what is the expected heart rate on the EKG?
- Less than 60 beats per minute (Correct answer)
- 60–80 beats per minute
- 80–100 beats per minute
- Greater than 100 beats per minute
Correct answer: Less than 60 beats per minute
Sinus bradycardia is defined as a regular sinus rhythm with a rate below 60 beats per minute. P waves are present and upright in lead II, each followed by a QRS complex, confirming the sinus origin of the rhythm.
EKG certification Certification EKG Certification Trivia 1
What is the normal range for the PR interval on a standard EKG?