ECG ECG Rhythm Interpretation 3

Question 1

A PR interval that is consistently prolonged beyond 0.20 seconds but every P wave conducts to a QRS indicates which rhythm?

Accepted Answer

First-degree AV block

Answer

A fixed, prolonged PR interval with every beat conducting defines first-degree AV block.

Question 2

A rhythm shows progressive PR interval lengthening until a QRS is dropped, then the cycle repeats. This describes which block?

Accepted Answer

Second-degree AV block Type I (Wenckebach)

Answer

Progressive PR lengthening followed by a dropped beat is the pattern of Mobitz I (Wenckebach).

Question 3

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

Accepted Answer

They are completely independent of each other

Answer

In complete heart block the atria and ventricles beat independently, so P waves and QRS complexes have no fixed relationship.

Question 4

A premature, wide, bizarre QRS complex that occurs earlier than expected with no preceding P wave is called what?

Accepted Answer

Premature ventricular contraction (PVC)

Answer

A wide, early QRS without a preceding P wave is a premature ventricular contraction.

Question 5

Second-degree AV block Type II (Mobitz II) is characterized by what pattern?

Accepted Answer

Constant PR interval with intermittent dropped QRS complexes

Answer

Mobitz II shows a fixed PR interval with sudden non-conducted P waves and dropped QRS complexes.

ECG (Electrocardiogram) Practice Test