DC Dysrhythmia Cardiac Rhythm Interpretation 2

Question 1

A patient's ECG shows a regular rhythm with a rate of 150 bpm, narrow QRS complexes, and no visible P waves before each QRS. What is the most likely dysrhythmia?

Accepted Answer

Atrial flutter with 2:1 block

Answer

Atrial flutter with 2:1 block classically presents at 150 bpm with flutter waves that may be buried in the QRS, producing apparent absence of discrete P waves.

Question 2

On a rhythm strip, the PR interval measures 0.28 seconds and is constant, with every P wave followed by a QRS complex. Which conduction abnormality is present?

Accepted Answer

First-degree AV block

Answer

First-degree AV block is characterized by a PR interval greater than 0.20 seconds that is constant, with every P wave conducting to a QRS.

Question 3

A rhythm strip shows grouped beating with progressive lengthening of the PR interval until a P wave fails to conduct, then the cycle repeats. This pattern describes which block?

Accepted Answer

Second-degree AV block Mobitz I (Wenckebach)

Answer

Mobitz I (Wenckebach) is defined by progressive PR prolongation until a QRS is dropped, creating grouped beating.

Question 4

Which ECG finding most strongly distinguishes ventricular tachycardia (VT) from supraventricular tachycardia (SVT) with aberrancy?

Accepted Answer

QRS duration greater than 0.14 seconds with AV dissociation

Answer

AV dissociation combined with a QRS wider than 0.14 seconds is the most reliable criterion for diagnosing VT over SVT with aberrancy.

Question 5

A patient's ECG shows a delta wave, short PR interval, and wide QRS. Which syndrome is associated with this pattern?

Accepted Answer

Wolff-Parkinson-White (WPW) syndrome

Answer

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

(DC) Dysrhythmia Certification Practice Test

(DC) Dysrhythmia Certification Practice Test

DC Dysrhythmia Cardiac Rhythm Interpretation 2