CCI ECG Rhythm Interpretation 3

Question 1

A rhythm strip shows irregularly irregular narrow QRS complexes with no discernible P waves and a wavy baseline. What is the diagnosis?

Accepted Answer

Atrial fibrillation

Answer

Atrial fibrillation produces an irregularly irregular ventricular response, absent organized P waves, and a fibrillatory baseline.

Question 2

What is the normal duration of the QRS complex in adults?

Accepted Answer

0.06–0.10 seconds

Answer

A normal QRS complex measures 0.06–0.10 seconds (60–100 ms); a duration ≥0.12 seconds is considered abnormally wide.

Question 3

Which lead is best used to identify P wave morphology and distinguish atrial rhythms?

Accepted Answer

Lead II

Answer

Lead II is parallel to the normal P wave vector, making P waves most upright and prominent, ideal for rhythm analysis.

Question 4

A patient's ECG shows a rhythm at 40 bpm with wide QRS complexes and no associated P waves. What rhythm is this?

Accepted Answer

Idioventricular rhythm

Answer

An idioventricular (ventricular escape) rhythm originates in the ventricles at 20–40 bpm with wide, bizarre QRS complexes and no P wave relationship.

Question 5

Torsades de pointes is most commonly associated with which ECG finding?

Accepted Answer

Prolonged QT interval

Answer

Torsades de pointes is a polymorphic ventricular tachycardia that occurs in the setting of a prolonged QT interval, which predisposes to triggered activity.

CCI - Cardiovascular Credentialing International Practice Test

CCI - Cardiovascular Credentialing International Practice Test

CCI ECG Rhythm Interpretation 3