ECG Lead Placement and Equipment Flashcards

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

Answer: Poor electrode contact or loose lead wire

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

V3 is placed between which two leads?

Answer: V2 and V4

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

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

Answer: Cleaning and lightly abrading the skin to reduce impedance

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

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

Answer: Respiratory movement causing electrode motion artifact

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

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

Answer: To reduce artifact and electrical noise without distorting waveforms

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

Right arm and left arm lead reversal will most noticeably affect which lead's appearance?

Answer: Lead I (inverted P, QRS, and T waves)

RA-LA reversal inverts all components of Lead I because the polarity of that lead is completely reversed.