Diagnostic Procedures and ECG Flashcards

In a standard 12-lead ECG, how many chest (precordial) leads are included?

Answer: 6

A 12-lead ECG includes 6 chest leads (V1–V6) and 6 limb leads (I, II, III, aVR, aVL, aVF).

What does the P wave on an ECG represent?

Answer: Atrial depolarization

The P wave represents atrial depolarization, which triggers the contraction of the atria.

Which ECG lead placement error is most likely to produce artifact?

Answer: Placing electrodes over bony prominences

Placing electrodes over bony prominences creates poor contact and increased artifact due to reduced conductivity.

Which preparation step is most important before placing ECG electrodes?

Answer: Clipping excessive hair and cleaning with alcohol

Cleaning the skin with alcohol and clipping hair removes oils and reduces impedance for better signal quality.

Where is the V1 electrode placed in a standard 12-lead ECG?

Answer: 4th intercostal space, right sternal border

V1 is placed at the 4th intercostal space along the right sternal border.

A somatic tremor artifact on an ECG is most likely caused by:

Answer: Patient muscle movement or shivering

Somatic tremor artifact results from voluntary or involuntary patient muscle movement and appears as irregular baseline wander.