CET Arrhythmia Recognition & Classification 2

Question 1

A patient's ECG shows a regular rhythm at 150 bpm with narrow QRS complexes and no visible P waves. Which arrhythmia is most likely?

Accepted Answer

Atrial flutter with 2:1 block

Answer

Atrial flutter with 2:1 block typically presents at ~150 bpm with flutter waves that may be hidden within QRS or T waves, producing a regular narrow-complex tachycardia.

Question 2

Which feature on an ECG best distinguishes Wolff-Parkinson-White (WPW) syndrome from a bundle branch block?

Accepted Answer

Delta wave at the onset of the QRS

Answer

The delta wave — a slurred upstroke at the beginning of the QRS — is the hallmark of WPW caused by ventricular pre-excitation via an accessory pathway.

Question 3

A rhythm strip shows P waves with at least three distinct morphologies and an irregular rate between 100–150 bpm. This is consistent with:

Accepted Answer

Multifocal atrial tachycardia (MAT)

Answer

MAT is defined by three or more distinct P-wave morphologies with a ventricular rate above 100 bpm, most commonly seen in patients with severe COPD.

Question 4

On an ECG, second-degree AV block Type II (Mobitz II) is characterized by:

Accepted Answer

Constant PR interval with sudden non-conducted P waves

Answer

Mobitz II features a fixed PR interval followed by an unexpected dropped QRS, indicating infranodal conduction failure and a higher risk of complete heart block.

Question 5

Which of the following arrhythmias is characterized by 'sawtooth' flutter waves at approximately 300 bpm on the ECG?

Accepted Answer

Atrial flutter

Answer

Atrial flutter produces characteristic sawtooth flutter waves (F waves) at ~300 bpm, best seen in leads II, III, aVF, and V1.

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CET Arrhythmia Recognition & Classification 2