ECG Clinical Applications

Question 1

What is the standard number of leads in a 12-lead ECG?

Accepted Answer

12 leads from 10 electrodes

Answer

A 12-lead ECG uses 10 physical electrodes (4 limb, 6 precordial) to generate 12 different electrical views of the heart.

Question 2

Where should the V4 precordial electrode be placed?

Accepted Answer

Fifth intercostal space at the midclavicular line

Answer

V4 is placed at the fifth intercostal space at the midclavicular line, serving as the reference point for V5 and V6 placement.

Question 3

Why is a baseline ECG important before starting certain medications?

Accepted Answer

To detect pre-existing QT prolongation or other abnormalities

Answer

A baseline ECG identifies pre-existing cardiac abnormalities (especially QT prolongation) that certain medications could worsen, preventing dangerous drug-induced arrhythmias.

Question 4

What artifact can be caused by patient movement during ECG recording?

Accepted Answer

Wandering baseline and muscle tremor artifact

Answer

Patient movement causes wandering baseline (slow undulation) and muscle tremor artifact (irregular, fine oscillations), which can obscure the true ECG signal.

Question 5

When should a 12-lead ECG be performed for a patient with chest pain?

Accepted Answer

Within 10 minutes of arrival

Answer

Guidelines recommend obtaining a 12-lead ECG within 10 minutes of arrival for any patient presenting with chest pain to rapidly identify acute myocardial infarction.

ECG Certification Practice Test

ECG Certification Practice Test

ECG Clinical Applications