ECG ECG Lead Placement and Equipment 3

Question 1

What is the most common cause of 60-Hz AC interference on an ECG?

Accepted Answer

Poor electrode contact or loose lead wire

Answer

60-Hz AC interference is most often caused by poor skin-electrode contact or a loose lead wire.

Question 2

V3 is placed between which two leads?

Accepted Answer

V2 and V4

Answer

V3 is placed directly between V2 and V4 to provide transitional precordial coverage.

Question 3

Which skin preparation step is most important before applying ECG electrodes?

Accepted Answer

Cleaning and lightly abrading the skin to reduce impedance

Answer

Cleaning and lightly abrading the skin removes dead cells and oils, significantly reducing electrode impedance.

Question 4

What does a wandering baseline on an ECG most commonly indicate?

Accepted Answer

Respiratory movement causing electrode motion artifact

Answer

A slow undulating baseline is typically caused by respiratory movement creating motion artifact at the electrode site.

Question 5

What is the purpose of the filter setting on an ECG machine?

Accepted Answer

To reduce artifact and electrical noise without distorting waveforms

Answer

ECG filters reduce high- and low-frequency noise while preserving clinically relevant waveform morphology.

ECG Certification Practice Test