PCT EKG Basics 3 — Questions and Answers
Question 1: Which arrhythmia is characterized by no discernible P waves and an irregularly irregular rhythm?
- Atrial flutter
- Atrial fibrillation (Correct answer)
- Junctional rhythm
- Sinus arrhythmia
Correct answer: Atrial fibrillation
Atrial fibrillation produces chaotic atrial activity with no identifiable P waves and a completely irregular ventricular response.
Question 2: A 'sawtooth' baseline pattern on an EKG is characteristic of:
- Atrial fibrillation
- Ventricular tachycardia
- Atrial flutter (Correct answer)
- Sinus bradycardia
Correct answer: Atrial flutter
Atrial flutter produces a characteristic sawtooth flutter wave pattern at approximately 300 beats per minute.
Question 3: What is the normal duration of the QRS complex?
- Less than 0.04 seconds
- 0.06–0.10 seconds (Correct answer)
- 0.12–0.20 seconds
- Greater than 0.20 seconds
Correct answer: 0.06–0.10 seconds
A normal QRS complex lasts 0.06 to 0.10 seconds; a duration ≥0.12 seconds suggests a bundle branch block or ventricular origin.
Question 4: Peaked, tall T waves in the precordial leads may indicate:
- Hypokalemia
- Hyperkalemia (Correct answer)
- Hypocalcemia
- Hyponatremia
Correct answer: Hyperkalemia
Hyperkalemia (elevated serum potassium) causes tall, narrow, peaked T waves, especially in precordial leads.
Question 5: Which part of the cardiac conduction system delays the impulse between the atria and ventricles?
- SA node
- Bundle of His
- AV node (Correct answer)
- Purkinje fibers
Correct answer: AV node
The AV node introduces a conduction delay that is reflected as the PR interval on the EKG, allowing atrial contraction before ventricular contraction.
Question 6: On an EKG, ST segment elevation may indicate:
- Atrial fibrillation
- Myocardial infarction (Correct answer)
- Bradycardia
- Bundle branch block
Correct answer: Myocardial infarction
ST segment elevation of 1 mm or more in two contiguous leads is a key indicator of acute myocardial infarction (STEMI).
Question 7: The PR interval on an EKG represents:
- Ventricular depolarization
- Time from atrial depolarization to start of ventricular depolarization (Correct answer)
- Ventricular repolarization
- Time from ventricular depolarization to repolarization
Correct answer: Time from atrial depolarization to start of ventricular depolarization
The PR interval measures conduction time from the start of atrial depolarization (P wave) through the AV node to the beginning of ventricular depolarization (QRS).
PCT EKG Basics 3
Which arrhythmia is characterized by no discernible P waves and an irregularly irregular rhythm?