Beat Reading Heart Beat Reading 2 — Questions and Answers
Question 1: A patient's ECG shows a PR interval of 0.28 seconds. This finding is most consistent with:
- First-degree AV block (Correct answer)
- Second-degree AV block Type I
- Second-degree AV block Type II
- Third-degree AV block
Correct answer: First-degree AV block
A PR interval greater than 0.20 seconds that is consistent and not associated with dropped beats indicates first-degree AV block.
Question 2: On a standard ECG tracing, what does the T wave represent?
- Atrial depolarization
- Ventricular depolarization
- Ventricular repolarization (Correct answer)
- Atrial repolarization
Correct answer: Ventricular repolarization
The T wave represents ventricular repolarization, the electrical recovery of the ventricles after contraction.
Question 3: Which rhythm is characterized by an irregularly irregular pattern with no identifiable P waves?
- Atrial flutter
- Atrial fibrillation (Correct answer)
- Sinus arrhythmia
- Multifocal atrial tachycardia
Correct answer: Atrial fibrillation
Atrial fibrillation produces an irregularly irregular rhythm with absent distinct P waves, replaced by chaotic fibrillatory baseline.
Question 4: A heart rate of 42 bpm with a normal P-QRS relationship is best described as:
- Sinus bradycardia (Correct answer)
- Junctional rhythm
- Idioventricular rhythm
- Sinus arrest
Correct answer: Sinus bradycardia
Sinus bradycardia is defined as a sinus-originated rhythm with a rate below 60 bpm with normal P wave morphology preceding each QRS.
Question 5: How many small squares on standard ECG paper equal one large square?
- 3
- 4
- 5 (Correct answer)
- 10
Correct answer: 5
Each large square on standard ECG paper contains 5 small squares, with each small square representing 0.04 seconds.
Question 6: ST-segment elevation in leads II, III, and aVF most likely indicates an acute MI affecting which wall?
- Anterior wall
- Lateral wall
- Inferior wall (Correct answer)
- Posterior wall
Correct answer: Inferior wall
Leads II, III, and aVF are inferior leads; ST elevation in these leads points to an inferior wall myocardial infarction.
Question 7: A QRS complex duration of 0.14 seconds indicates:
- Normal ventricular conduction
- First-degree block
- Bundle branch block or aberrant conduction (Correct answer)
- Accelerated junctional rhythm
Correct answer: Bundle branch block or aberrant conduction
A QRS wider than 0.12 seconds (3 small squares) suggests bundle branch block or abnormal ventricular conduction.
Beat Reading Heart Beat Reading 2
A patient's ECG shows a PR interval of 0.28 seconds.
This finding is most consistent with: