ACLS ACLS Cardiac Rhythms & ECG Interpretation

Question 1

On an ECG, what characteristic finding confirms ventricular fibrillation (VF)?

Accepted Answer

Chaotic, disorganized electrical activity with no identifiable QRS complexes

Answer

Regular wide QRS complexes at >150 bpm

Answer

Regular narrow QRS complexes at 300 bpm

Answer

P waves with prolonged PR interval

Question 2

Which ECG rhythm is characterized by a regularly irregular pattern with no P waves and a sawtooth baseline at ~300 bpm?

Accepted Answer

Atrial flutter

Answer

Atrial fibrillation

Answer

Multifocal atrial tachycardia

Answer

AV nodal reentrant tachycardia

Question 3

In ACLS, pulseless electrical activity (PEA) is best described as:

Accepted Answer

An organized ECG rhythm without a palpable pulse

Answer

VF with a detectable pulse

Answer

Asystole with occasional P waves

Answer

Rapid wide-complex tachycardia

Question 4

What is the hallmark ECG finding of first-degree AV block?

Accepted Answer

PR interval > 200 ms with every P wave followed by a QRS

Answer

Dropped QRS complexes

Answer

Progressive PR lengthening

Answer

Complete dissociation of P and QRS

Question 5

Which type of second-degree AV block is considered more dangerous and often requires pacing?

Accepted Answer

Mobitz Type II

Answer

Mobitz Type I (Wenckebach)

Answer

First-degree AV block

Answer

Accelerated junctional rhythm

Question 6

What ECG finding is the hallmark of Wolff-Parkinson-White (WPW) syndrome?

Accepted Answer

Delta wave with short PR interval

Answer

Prolonged QT interval

Answer

Tall peaked T waves

Answer

Prominent U waves