ACLS ACLS Cardiac Rhythms and ECG Interpretation 1 — Questions and Answers
Question 1: Which cardiac rhythm is characterized by no discernible P waves, a coarse irregular baseline, and no organized QRS complexes?
- Ventricular fibrillation (VF) (Correct answer)
- Ventricular tachycardia (VT)
- Asystole
- Atrial fibrillation
Correct answer: Ventricular fibrillation (VF)
Ventricular fibrillation presents as a chaotic, irregular waveform with no identifiable P waves or QRS complexes, indicating disorganized ventricular electrical activity.
Question 2: In ACLS, what is the treatment for pulseless electrical activity (PEA)?
- CPR + epinephrine + identify and treat reversible causes (H's and T's) (Correct answer)
- Immediate defibrillation
- Synchronized cardioversion
- Atropine 1 mg IV
Correct answer: CPR + epinephrine + identify and treat reversible causes (H's and T's)
PEA is treated with high-quality CPR, epinephrine every 3–5 minutes, and systematic search for reversible causes using the H's and T's framework.
Question 3: A patient has a wide-complex tachycardia at 180 bpm with no pulse. What is the correct ACLS intervention?
- Unsynchronized defibrillation (shock) (Correct answer)
- Synchronized cardioversion
- Amiodarone 300 mg IV
- Adenosine 6 mg IV rapid push
Correct answer: Unsynchronized defibrillation (shock)
Pulseless wide-complex tachycardia (presumed VT/VF) is treated with immediate unsynchronized defibrillation as part of the pulseless VT/VF algorithm.
Question 4: What does a 'tombstone' ST elevation pattern on ECG indicate in the context of ACLS?
- ST-elevation myocardial infarction (STEMI) (Correct answer)
- Normal sinus rhythm variant
- Pericarditis
- Benign early repolarization
Correct answer: ST-elevation myocardial infarction (STEMI)
Tombstone ST elevation — dramatic, dome-shaped ST elevation — is a pattern associated with massive STEMI requiring emergent reperfusion.
Question 5: Which rhythm on ECG shows regular narrow QRS complexes at 150 bpm with a 'sawtooth' baseline pattern?
- Atrial flutter with 2:1 block (Correct answer)
- Sinus tachycardia
- Atrial fibrillation
- Junctional tachycardia
Correct answer: Atrial flutter with 2:1 block
Atrial flutter classically presents with a sawtooth flutter wave baseline at ~300 bpm and a ventricular rate of 150 bpm in 2:1 conduction.
Question 6: What is the significance of a prolonged QT interval in ACLS management?
- Increased risk of torsades de pointes (polymorphic VT) (Correct answer)
- Indicates complete heart block
- Is a normal finding requiring no treatment
- Indicates hyperkalemia
Correct answer: Increased risk of torsades de pointes (polymorphic VT)
A prolonged QT interval indicates delayed ventricular repolarization, which predisposes to torsades de pointes — a potentially fatal polymorphic ventricular tachycardia.
ACLS ACLS Cardiac Rhythms and ECG Interpretation 1
Which cardiac rhythm is characterized by no discernible P waves, a coarse irregular baseline, and no organized QRS complexes?