NRCMA EKG Basics 2 — Questions and Answers
Question 1: Which EKG finding is most characteristic of hyperkalemia?
- Peaked T waves (Correct answer)
- Prolonged QT interval
- Delta waves
- ST elevation
Correct answer: Peaked T waves
Hyperkalemia classically produces tall, peaked (tent-shaped) T waves on EKG.
Question 2: On a standard EKG, the PR interval is measured from the beginning of the P wave to the beginning of which wave?
- Q wave (Correct answer)
- R wave
- S wave
- T wave
Correct answer: Q wave
The PR interval spans from the onset of the P wave to the onset of the QRS complex (Q wave).
Question 3: A patient's EKG shows no visible P waves and an irregularly irregular rhythm. Which arrhythmia does this most likely represent?
- Atrial fibrillation (Correct answer)
- Ventricular tachycardia
- Atrial flutter
- Sinus bradycardia
Correct answer: Atrial fibrillation
Atrial fibrillation produces absent distinct P waves and an irregularly irregular ventricular response.
Question 4: The QT interval represents which phase of the cardiac cycle?
- Total ventricular depolarization and repolarization (Correct answer)
- Atrial depolarization only
- AV nodal conduction delay
- Sinoatrial node firing
Correct answer: Total ventricular depolarization and repolarization
The QT interval encompasses the entire period of ventricular electrical activity — both depolarization and repolarization.
Question 5: Which lead configuration views the inferior wall of the heart?
- Leads II, III, and aVF (Correct answer)
- Leads I and aVL
- Leads V1 and V2
- Leads V4, V5, and V6
Correct answer: Leads II, III, and aVF
The inferior leads — II, III, and aVF — reflect electrical activity from the bottom surface of the heart.
Question 6: An EKG strip shows a PR interval of 0.28 seconds. This finding is consistent with:
- First-degree AV block (Correct answer)
- Second-degree AV block type I
- Third-degree AV block
- Bundle branch block
Correct answer: First-degree AV block
A PR interval greater than 0.20 seconds (one large box) that is constant indicates first-degree AV block.
Question 7: Which waveform on an EKG represents ventricular repolarization?
- T wave (Correct answer)
- P wave
- QRS complex
- U wave
Correct answer: T wave
The T wave reflects ventricular repolarization as the ventricles reset electrically after contraction.
NRCMA EKG Basics 2
Which EKG finding is most characteristic of hyperkalemia?