DC Dysrhythmia ECG Monitoring & Analysis 2

Question 1

On a rhythm strip, the PR interval measures 0.28 seconds. This finding is most consistent with:

Accepted Answer

First-degree AV block

Answer

A PR interval greater than 0.20 seconds indicates first-degree AV block, which is a consistent prolongation without dropped beats.

Question 2

A patient's ECG shows P waves that progressively lengthen their PR intervals until a QRS is dropped, then the cycle repeats. This pattern describes:

Accepted Answer

Mobitz Type I (Wenckebach)

Answer

Progressive PR prolongation followed by a non-conducted P wave is the hallmark of Mobitz Type I (Wenckebach) second-degree AV block.

Question 3

Which ECG finding best differentiates ventricular tachycardia from supraventricular tachycardia with aberrant conduction?

Accepted Answer

AV dissociation

Answer

AV dissociation, where P waves and QRS complexes fire independently, is the most reliable ECG differentiator of ventricular tachycardia.

Question 4

A rhythm strip shows no identifiable P waves, an irregularly irregular ventricular response, and a rate of 110 bpm. The most likely diagnosis is:

Accepted Answer

Atrial fibrillation

Answer

Absent P waves with an irregularly irregular ventricular rate are the classic hallmarks of atrial fibrillation.

Question 5

The QT interval on a rhythm strip should be corrected for heart rate using Bazett's formula. A corrected QT (QTc) greater than what value is considered prolonged in adults?

Accepted Answer

0.44 seconds

Answer

A QTc exceeding 0.44 seconds (440 ms) is generally considered prolonged and associated with increased risk of torsades de pointes.

(DC) Dysrhythmia Certification Practice Test

(DC) Dysrhythmia Certification Practice Test

DC Dysrhythmia ECG Monitoring & Analysis 2