EKG certification Certification EKG Electrode Placement & Lead Systems 2 — Questions and Answers
Question 1: When performing a 12-lead EKG, where should the V4 electrode be placed?
- Fifth intercostal space, midclavicular line (Correct answer)
- Fourth intercostal space, left sternal border
- Fifth intercostal space, left midaxillary line
- Fifth intercostal space, left anterior axillary line
Correct answer: Fifth intercostal space, midclavicular line
V4 is placed at the fifth intercostal space at the left midclavicular line.
Question 2: Which leads are considered the inferior leads on a 12-lead EKG?
- II, III, and aVF (Correct answer)
- I, aVL, and V5
- V1, V2, and V3
- aVR, aVL, and aVF
Correct answer: II, III, and aVF
Leads II, III, and aVF view the inferior wall of the heart supplied by the right coronary artery.
Question 3: What is the correct limb electrode placement for a standard 12-lead EKG?
- RA on right arm, LA on left arm, RL on right leg, LL on left leg (Correct answer)
- RA on right leg, LA on left arm, RL on right arm, LL on left leg
- RA on right arm, LA on left leg, RL on right leg, LL on left arm
- RA on left arm, LA on right arm, RL on left leg, LL on right leg
Correct answer: RA on right arm, LA on left arm, RL on right leg, LL on left leg
Standard placement uses RA on the right arm, LA on the left arm, RL on the right leg, and LL on the left leg.
Question 4: Lead aVR provides an electrical view of the heart from which perspective?
- Right shoulder toward the heart (Correct answer)
- Left lateral wall
- Inferior wall
- Posterior wall
Correct answer: Right shoulder toward the heart
Lead aVR views the heart from the right shoulder perspective, looking at the right atrium and outflow tract.
Question 5: If the V1 and V2 electrodes are placed too high on the chest, what is the most likely effect on the EKG tracing?
- Altered R-wave progression mimicking septal pathology (Correct answer)
- Increased amplitude of P waves in all leads
- Baseline artifact from skeletal muscle
- Prolonged QT interval across precordial leads
Correct answer: Altered R-wave progression mimicking septal pathology
High placement of V1 and V2 can reduce R-wave amplitude and simulate anterior septal abnormalities.
Question 6: In Einthoven's triangle, Lead I measures the potential difference between which two electrodes?
- Left arm (positive) and right arm (negative) (Correct answer)
- Right arm (positive) and left leg (negative)
- Left leg (positive) and right arm (negative)
- Left arm (positive) and left leg (negative)
Correct answer: Left arm (positive) and right arm (negative)
Lead I records the voltage difference from the right arm (negative) to the left arm (positive).
EKG certification Certification EKG Electrode Placement & Lead Systems 2
When performing a 12-lead EKG, where should the V4 electrode be placed?