CCS Cardiac Rhythm Interpretation & ECG Analysis

Question 1

What is the normal PR interval on a standard 12-lead ECG?

Accepted Answer

0.12–0.20 seconds

Answer

0.04–0.08 seconds

Answer

0.25–0.35 seconds

Answer

0.06–0.10 seconds

Question 2

Which ECG finding is characteristic of first-degree AV block?

Accepted Answer

Consistently prolonged PR interval greater than 0.20 seconds with all P waves conducted

Answer

Dropped QRS complexes following P waves

Answer

Progressive PR interval lengthening until a QRS is dropped

Answer

Complete dissociation between P waves and QRS complexes

Question 3

What heart rate range defines sinus bradycardia in an adult?

Accepted Answer

Less than 60 bpm

Answer

Less than 40 bpm

Answer

40–50 bpm only

Answer

Less than 50 bpm

Question 4

On a standard ECG, what physiologic event does the QRS complex represent?

Accepted Answer

Ventricular depolarization

Answer

Atrial depolarization

Answer

Ventricular repolarization

Answer

AV nodal conduction delay

Question 5

What is the normal QRS duration on an ECG?

Accepted Answer

0.06–0.10 seconds

Answer

0.04–0.08 seconds

Answer

0.12–0.20 seconds

Answer

0.20–0.40 seconds

Question 6

Which rhythm is characterized by an irregularly irregular ventricular response with no discernible P waves?

Accepted Answer

Atrial fibrillation

Answer

Atrial flutter

Answer

Junctional tachycardia

Answer

Multifocal atrial tachycardia

Question 7

What does the T wave on a surface ECG represent?

Accepted Answer

Ventricular repolarization

Answer

Atrial depolarization

Answer

Atrial repolarization

Answer

Ventricular depolarization