EKG certification Certification EKG Certification Trivia 1

Question 1

What is the normal range for the PR interval on a standard EKG?

Accepted Answer

0.12–0.20 seconds

Answer

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?

Accepted Answer

Mobitz Type I (Wenckebach) block

Answer

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?

Accepted Answer

5 large squares

Answer

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?

Accepted Answer

Right coronary artery

Answer

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?

Accepted Answer

Tall, peaked T waves

Answer

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.

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EKG certification Certification EKG Certification Trivia 1