AF Electrophysiology & ECG Interpretation

Question 1

What is the characteristic ECG finding that distinguishes atrial fibrillation from normal sinus rhythm?

Accepted Answer

Absence of distinct P waves with an irregularly irregular ventricular rhythm

Answer

Peaked T waves with prolonged QT interval

Answer

Regular sawtooth baseline waves at 300 bpm

Answer

Wide QRS complexes with left bundle branch block pattern

Question 2

What is the typical atrial rate during atrial fibrillation?

Accepted Answer

350–600 impulses per minute

Answer

60–100 impulses per minute

Answer

250–350 impulses per minute

Answer

150–250 impulses per minute

Question 3

In atrial fibrillation, the RR intervals on the ECG are best described as:

Accepted Answer

Irregularly irregular with no repeating pattern

Answer

Fixed at 0.60 seconds

Answer

Regularly irregular with group beating

Answer

Regular with rare ectopic beats

Question 4

Which ECG lead is most useful for identifying fibrillatory (f) waves in atrial fibrillation?

Accepted Answer

Lead V1

Answer

Lead I

Answer

Lead aVR

Answer

Lead V5

Question 5

In uncomplicated atrial fibrillation, the QRS complex width is typically:

Accepted Answer

Between 0.08–0.12 seconds (narrow)

Answer

Greater than 0.12 seconds (wide)

Answer

Absent due to ventricular standstill

Answer

Exactly 0.20 seconds

Question 6

How is atrial flutter differentiated from atrial fibrillation on ECG?

Accepted Answer

Atrial flutter shows organized sawtooth waves at 250–350 bpm

Answer

Atrial flutter has an irregularly irregular ventricular response

Answer

Atrial fibrillation has a regular ventricular rate of 150 bpm

Answer

Atrial flutter has no visible atrial activity on ECG

Question 7

The PR interval in a patient with atrial fibrillation:

Accepted Answer

Cannot be measured because distinct P waves are absent

Answer

Is consistently prolonged at 0.24 seconds

Answer

Is shortened due to enhanced AV conduction

Answer

Remains fixed at 0.20 seconds throughout