ECG ECG in Clinical Practice 3

Question 1

Which lead configuration would produce a completely flat line (asystole appearance) if a limb lead becomes disconnected?

Accepted Answer

The affected lead traces flat while others remain

Answer

All leads go flat simultaneously

Answer

Only the chest leads are affected

Answer

The ECG stops printing entirely

Question 2

A regular narrow-complex tachycardia at 150 bpm with no visible P waves most likely represents what?

Accepted Answer

Supraventricular tachycardia

Answer

Ventricular tachycardia

Answer

Sinus bradycardia

Answer

First-degree AV block

Question 3

What does the PR interval represent on an ECG?

Accepted Answer

Time from atrial depolarization to ventricular depolarization

Answer

Time for ventricular repolarization

Answer

Duration of the QRS complex

Answer

Time for atrial repolarization only

Question 4

Which artifact appears as consistent, fine, fast oscillations often caused by 60 Hz electrical sources?

Accepted Answer

AC electrical interference

Answer

Wandering baseline

Answer

Muscle tremor artifact

Answer

Somatic tremor

Question 5

A normal QRS complex duration should be less than which value?

Accepted Answer

0.12 seconds

Answer

0.20 seconds

Answer

0.40 seconds

Answer

0.06 seconds

Question 6

If the limb leads on the right and left arms are reversed, what change is commonly seen?

Accepted Answer

Lead I becomes inverted

Answer

V1 becomes inverted

Answer

The QRS widens abnormally

Answer

The heart rate doubles

Question 7

Which of the following patients requires modified electrode placement using a right-sided ECG?

Accepted Answer

Suspected right ventricular infarction

Answer

Suspected pericarditis

Answer

Atrial fibrillation

Answer

Sinus tachycardia