CRAT Atrioventricular (AV) Blocks 3

Question 1

On the ECG, which measurement defines a normal PR interval?

Accepted Answer

120-200 ms

Answer

60-100 ms

Answer

200-240 ms

Answer

80-120 ms

Question 2

In high-degree AV block with a 4:1 conduction ratio, what is the ventricular rate if the atrial rate is 80 bpm?

Accepted Answer

20 bpm

Answer

40 bpm

Answer

80 bpm

Answer

10 bpm

Question 3

Which characteristic of the QRS complex in complete heart block provides a clue about the location of the escape pacemaker?

Accepted Answer

Narrow QRS suggests a junctional escape; wide QRS suggests a ventricular escape

Answer

Wide QRS always indicates atrial origin

Answer

Narrow QRS indicates ventricular origin

Answer

QRS width is unrelated to escape pacemaker location

Question 4

Which medication is a common pharmacological cause of AV block?

Accepted Answer

Digoxin

Answer

Atropine

Answer

Epinephrine

Answer

Dopamine

Question 5

AV dissociation that is NOT due to complete heart block can occur in which situation?

Accepted Answer

Accelerated junctional rhythm that exceeds the sinus rate

Answer

Normal sinus rhythm

Answer

Atrial flutter with 2:1 block

Answer

First-degree AV block

Question 6

In a rhythm strip, you observe regular P waves at 75 bpm and regular wide QRS complexes at 35 bpm with no consistent PR relationship. Which rhythm is present?

Accepted Answer

Third-degree (complete) AV block with ventricular escape rhythm

Answer

Mobitz type II second-degree AV block

Answer

Atrial flutter with variable block

Answer

Accelerated idioventricular rhythm