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

Every P wave is followed by a QRS complex with a prolonged PR interval

Answer

P waves are absent and only QRS complexes are visible

Answer

The PR interval progressively lengthens until a QRS is dropped

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

Prolonged QT interval with U waves

Answer

Shortened PR interval and delta waves

Answer

ST depression in lateral leads only

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

Amiodarone 150 mg IV over 10 minutes

Answer

Metoprolol 5 mg IV

Answer

Verapamil 2.5 mg IV

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

Second-degree AV block Mobitz type I

Answer

Second-degree AV block Mobitz type II

Answer

Third-degree AV block

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

Progressive PR lengthening followed by a dropped QRS

Answer

Complete P-QRS dissociation

Answer

Alternating bundle branch block patterns

Question 6

What ECG pattern is classically associated with right ventricular MI and should prompt right-sided lead placement?

Accepted Answer

ST elevation in leads II, III, aVF — especially with ST elevation in V1

Answer

ST elevation in V1–V4 with left axis deviation

Answer

ST depression in aVL with tall R in V1

Answer

New left bundle branch block with ST elevation in V5–V6