CPR ECG Rhythm Interpretation 3

Question 1

In Mobitz Type II second-degree AV block, which ECG finding differentiates it from Mobitz Type I?

Accepted Answer

Constant PR interval with sudden non-conducted P wave

Answer

Mobitz Type II features a constant PR interval followed by a sudden dropped QRS, whereas Mobitz Type I has progressive PR lengthening (Wenckebach).

Question 2

A patient's ECG shows P waves and QRS complexes occurring independently with no relationship to each other. The ventricular rate is 38 bpm with wide QRS complexes. What is the rhythm?

Accepted Answer

Complete (third-degree) AV block

Answer

Complete (third-degree) AV block is characterized by complete AV dissociation where the atria and ventricles beat independently, and a wide QRS with slow rate indicates a ventricular escape pacemaker.

Question 3

Which of the following best describes torsades de pointes on ECG?

Accepted Answer

Polymorphic VT where QRS axis twists around the isoelectric line

Answer

Torsades de pointes is a polymorphic ventricular tachycardia in which the QRS amplitude and axis appear to rotate or twist around the baseline.

Question 4

A 45-year-old presents with palpitations. ECG shows a short PR interval of 0.10 seconds, a slurred upstroke on the QRS (delta wave), and a wide QRS. What syndrome does this suggest?

Accepted Answer

Wolff-Parkinson-White syndrome

Answer

WPW syndrome is characterized by a short PR interval, delta wave (slurred QRS upstroke), and widened QRS due to pre-excitation via an accessory pathway.

Question 5

On an ECG, which lead configuration is best for identifying P wave morphology and diagnosing atrial rhythms?

Accepted Answer

Lead II

Answer

Lead II is most commonly used to evaluate P wave morphology because it is oriented along the main atrial vector, producing the tallest and most upright P waves.

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(CPR) Certified Paramedic Response Practice Test

CPR ECG Rhythm Interpretation 3