DC Dysrhythmia Pathophysiology & Electrophysiology

Question 1

What is the normal pacemaker of the heart and its intrinsic rate?

Accepted Answer

SA node, 60–100 bpm

Answer

AV node, 40–60 bpm

Answer

Bundle of His, 20–40 bpm

Answer

Purkinje fibers, 60–100 bpm

Question 2

What is the primary function of the AV node in cardiac conduction?

Accepted Answer

Delay impulse transmission to allow ventricular filling

Answer

Initiate the cardiac impulse

Answer

Distribute the impulse through the ventricles via Purkinje fibers

Answer

Prevent retrograde conduction from ventricles to atria

Question 3

Which structure divides into the right and left bundle branches?

Accepted Answer

Bundle of His

Answer

Sinoatrial node

Answer

AV node

Answer

Purkinje fibers

Question 4

What is the intrinsic escape rate of AV junctional tissue if the SA node fails?

Accepted Answer

40–60 bpm

Answer

20–40 bpm

Answer

60–100 bpm

Answer

100–150 bpm

Question 5

In which direction does normal ventricular depolarization travel through the Purkinje network?

Accepted Answer

From endocardium to epicardium

Answer

From epicardium to endocardium

Answer

Exclusively from right to left ventricle

Answer

From cardiac apex toward the base

Question 6

What ECG change results from slowed conduction through the AV node?

Accepted Answer

Prolonged PR interval beyond 0.20 seconds

Answer

Widened QRS complex

Answer

Elevated ST segment

Answer

Inverted T wave