ECG ECG Rhythm Interpretation 2 — Questions and Answers
Question 1: A rhythm strip shows no identifiable P waves and a chaotic, irregularly irregular baseline with a ventricular rate of 130 bpm. What rhythm is this?
- Atrial fibrillation (Correct answer)
- Atrial flutter
- Sinus tachycardia
- First-degree AV block
Correct answer: Atrial fibrillation
Absent P waves with an irregularly irregular ventricular response is the hallmark of atrial fibrillation.
Question 2: A sawtooth baseline pattern with atrial waves at about 300 bpm and a regular 2:1 ventricular response best describes which rhythm?
- Atrial flutter (Correct answer)
- Atrial fibrillation
- Ventricular tachycardia
- Sinus rhythm
Correct answer: Atrial flutter
The sawtooth flutter waves near 300 bpm with a fixed conduction ratio are classic for atrial flutter.
Question 3: On a normal ECG, which part of the conduction system creates the brief pause seen in the PR interval?
- AV node (Correct answer)
- SA node
- Purkinje fibers
- Bundle of His
Correct answer: AV node
The AV node deliberately delays the impulse, producing the PR interval and allowing ventricular filling.
Question 4: A wide-complex regular tachycardia at 180 bpm with no visible P waves is most concerning for which rhythm?
- Ventricular tachycardia (Correct answer)
- Sinus tachycardia
- Atrial flutter
- Junctional rhythm
Correct answer: Ventricular tachycardia
A regular wide-QRS tachycardia without P waves should be treated as ventricular tachycardia until proven otherwise.
Question 5: Which finding on a rhythm strip indicates a normal sinus rhythm?
- Upright P wave before every QRS at 60-100 bpm (Correct answer)
- Absent P waves at 40 bpm
- Sawtooth flutter waves
- Chaotic wavy baseline
Correct answer: Upright P wave before every QRS at 60-100 bpm
Normal sinus rhythm shows a consistent upright P wave preceding each QRS at a rate of 60-100 bpm.
Question 6: A rhythm shows a rate of 45 bpm with normal P waves, PR intervals, and QRS complexes. What is this rhythm?
- Sinus bradycardia (Correct answer)
- Sinus tachycardia
- Complete heart block
- Atrial fibrillation
Correct answer: Sinus bradycardia
A normal sinus pattern with a rate below 60 bpm is sinus bradycardia.
Question 7: In ventricular fibrillation, the ECG most characteristically shows what?
- Chaotic waveforms with no identifiable QRS complexes (Correct answer)
- Regular narrow QRS at 75 bpm
- Sawtooth atrial waves
- A flat isoelectric line
Correct answer: Chaotic waveforms with no identifiable QRS complexes
Ventricular fibrillation produces disorganized, chaotic deflections with no discernible QRS complexes.
ECG ECG Rhythm Interpretation 2
A rhythm strip shows no identifiable P waves and a chaotic, irregularly irregular baseline with a ventricular rate of 130 bpm.
What rhythm is this?