ACLS ACLS Cardiac Rhythm Recognition 2

Question 1

In third-degree (complete) heart block, what is the relationship between P waves and QRS complexes?

Accepted Answer

P waves and QRS complexes are completely dissociated with no consistent relationship

Answer

In complete heart block, the atria and ventricles beat independently with no relationship between P waves and QRS complexes — the PR interval varies randomly.

Question 2

Which ECG finding is most consistent with hyperkalemia in a symptomatic patient?

Accepted Answer

Tall peaked T waves and widened QRS complexes

Answer

Hyperkalemia classically produces tall, peaked T waves followed by widening of the QRS and, if untreated, can progress to a sine-wave pattern and cardiac arrest.

Question 3

A patient presents with a regular narrow-complex tachycardia at 150 bpm. Vagal maneuvers fail. Which drug is given first?

Accepted Answer

Adenosine 6 mg IV rapid push

Answer

Adenosine 6 mg given as a rapid IV push is the first-line drug for stable narrow-complex SVT after failed vagal maneuvers.

Question 4

On the ECG, a PR interval greater than 200 ms that is constant with all P waves conducted defines:

Accepted Answer

First-degree AV block

Answer

First-degree AV block is defined by a PR interval >200 ms (one large box) that is constant, with every P wave followed by a QRS complex.

Question 5

Which of the following best describes Mobitz Type II second-degree AV block?

Accepted Answer

Constant PR interval with sudden dropped QRS complexes without warning

Answer

Mobitz Type II shows a constant PR interval with intermittent, unpredictable failure of conduction — a QRS complex simply drops without progressive PR lengthening.

ACLS Practice Test

ACLS Practice Test

ACLS ACLS Cardiac Rhythm Recognition 2