NHI Electrocardiography and Cardiac Monitoring 2

Question 1

Where should the RA (right arm) electrode be placed for a 12-lead ECG?

Accepted Answer

On the right arm above the wrist

Answer

The RA electrode is placed on the right arm, typically above the wrist, to record the electrical potential from the right upper extremity.

Question 2

Which electrode serves as the electrical ground in a standard 12-lead ECG?

Accepted Answer

RL (right leg)

Answer

The RL (right leg) electrode is the ground electrode; it reduces electrical interference and is not used to form any of the 12 leads.

Question 3

Somatic tremor artifact on an ECG is most commonly caused by:

Accepted Answer

Involuntary patient movement or muscle activity

Answer

Somatic tremor artifact results from voluntary or involuntary patient muscle movement, causing irregular baseline disturbances on the ECG tracing.

Question 4

The normal PR interval duration on an ECG is:

Accepted Answer

0.12–0.20 seconds

Answer

The normal PR interval is 0.12 to 0.20 seconds, representing conduction time from the atria through the AV node to the ventricles.

Question 5

Which precordial lead is placed at the 5th intercostal space, left midclavicular line?

Accepted Answer

V4

Answer

V4 is placed at the 5th intercostal space at the left midclavicular line, an important landmark for accurate precordial lead positioning.

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