CPR ECG Rhythm Interpretation 2 — Questions and Answers
Question 1: A patient presents with an irregular rhythm, no discernible P waves, and an irregularly irregular ventricular rate of 110 bpm. What is the most likely rhythm?
- Atrial flutter with variable block
- Atrial fibrillation (Correct answer)
- Multifocal atrial tachycardia
- Wandering atrial pacemaker
Correct answer: Atrial fibrillation
Atrial fibrillation is characterized by an irregularly irregular ventricular response and absent distinct P waves, replaced by fibrillatory baseline.
Question 2: On an ECG, you observe a regular rhythm at 150 bpm with sawtooth flutter waves most visible in leads II, III, and aVF. What is the atrial rate most commonly associated with this rhythm?
- 200-250 bpm
- 250-300 bpm
- 300-350 bpm (Correct answer)
- 350-400 bpm
Correct answer: 300-350 bpm
Atrial flutter typically has an atrial rate of 300-350 bpm, commonly presenting with 2:1 conduction yielding a ventricular rate near 150 bpm.
Question 3: A patient's ECG shows a QRS complex of 0.14 seconds with a right bundle branch block morphology and a rate of 180 bpm with no visible P waves. What rhythm should you suspect?
- Supraventricular tachycardia with aberrancy
- Ventricular tachycardia (Correct answer)
- Accelerated idioventricular rhythm
- Torsades de pointes
Correct answer: Ventricular tachycardia
A wide-complex tachycardia at 180 bpm without visible P waves is ventricular tachycardia until proven otherwise, even if RBBB morphology is present.
Question 4: Which ECG finding is most characteristic of hyperkalemia?
- Prolonged QT interval
- Peaked, narrow, symmetric T waves (Correct answer)
- Prominent U waves
- Delta waves with short PR interval
Correct answer: Peaked, narrow, symmetric T waves
Hyperkalemia classically produces tall, peaked, narrow, and symmetric T waves, especially prominent in precordial leads.
Question 5: A patient in cardiac arrest has ECG showing organized electrical activity but no palpable pulse. Which rhythm is present?
- Asystole
- Ventricular fibrillation
- Pulseless electrical activity (Correct answer)
- Fine ventricular fibrillation
Correct answer: Pulseless electrical activity
Pulseless electrical activity (PEA) is defined as organized cardiac electrical activity on ECG without a palpable pulse.
Question 6: On a 12-lead ECG, ST elevation in leads II, III, and aVF with reciprocal depression in leads I and aVL suggests occlusion of which artery?
- Left anterior descending artery
- Left circumflex artery
- Right coronary artery (Correct answer)
- Left main coronary artery
Correct answer: Right coronary artery
Inferior STEMI (ST elevation in II, III, aVF) with reciprocal lateral changes is most commonly caused by right coronary artery occlusion.
Question 7: What is the PR interval range that defines first-degree AV block in adults?
- Greater than 0.12 seconds
- Greater than 0.16 seconds
- Greater than 0.20 seconds (Correct answer)
- Greater than 0.24 seconds
Correct answer: Greater than 0.20 seconds
First-degree AV block is defined as a PR interval consistently greater than 0.20 seconds (200 ms) with all P waves conducted.
CPR ECG Rhythm Interpretation 2
A patient presents with an irregular rhythm, no discernible P waves, and an irregularly irregular ventricular rate of 110 bpm.
What is the most likely rhythm?