EKG certification Certification EKG Technician Certification 1 — Questions and Answers
Question 1: Which of the following correctly describes the normal PR interval on an adult EKG?
- 0.04–0.10 seconds
- 0.12–0.20 seconds (Correct answer)
- 0.22–0.30 seconds
- 0.30–0.40 seconds
Correct answer: 0.12–0.20 seconds
The normal PR interval ranges from 0.12 to 0.20 seconds (3–5 small squares). A PR interval longer than 0.20 seconds indicates first-degree AV block, while a shorter interval may suggest a pre-excitation syndrome such as Wolff-Parkinson-White.
Question 2: When applying electrodes for a 12-lead EKG, where should the RA (right arm) limb electrode be placed?
- On the right leg above the ankle
- On the right wrist or anywhere on the right arm (Correct answer)
- On the left arm at the shoulder
- On the right side of the chest at the fourth intercostal space
Correct answer: On the right wrist or anywhere on the right arm
The RA electrode should be placed on the right wrist or anywhere on the right arm, typically avoiding bony prominences. Limb electrodes can be placed anywhere on the respective limb as long as placement is consistent, because they measure potential differences between limbs.
Question 3: A patient's EKG shows a rhythm with no identifiable P waves and an irregularly irregular ventricular response. What rhythm does this most likely represent?
- Atrial flutter
- Atrial fibrillation (Correct answer)
- Junctional tachycardia
- Second-degree AV block type I
Correct answer: Atrial fibrillation
Atrial fibrillation is characterized by absent distinct P waves (replaced by chaotic fibrillatory baseline) and an irregularly irregular ventricular response. Atrial flutter typically shows a regular sawtooth pattern, and junctional rhythms usually have retrograde or absent P waves with a regular rate.
Question 4: What is the correct paper speed used for a standard resting 12-lead EKG?
- 10 mm/sec
- 25 mm/sec (Correct answer)
- 50 mm/sec
- 100 mm/sec
Correct answer: 25 mm/sec
The standard paper speed for a resting 12-lead EKG is 25 mm/sec. At this speed, each small square (1 mm) represents 0.04 seconds and each large square (5 mm) represents 0.20 seconds. Some countries use 50 mm/sec for pediatric tracings, but 25 mm/sec is the universal standard for adults.
Question 5: An EKG tracing shows ST-segment elevation in leads V1 through V4. Which region of the myocardium is most likely affected?
- Inferior wall
- Lateral wall
- Anterior wall (Correct answer)
- Posterior wall
Correct answer: Anterior wall
Leads V1–V4 are the precordial leads that overlie the anterior surface of the heart. ST elevation in these leads suggests anterior wall myocardial injury or infarction, most commonly due to occlusion of the left anterior descending (LAD) artery.
Question 6: What does the QRS complex on an EKG represent?
- Atrial depolarization
- Ventricular repolarization
- Ventricular depolarization (Correct answer)
- AV node conduction delay
Correct answer: Ventricular depolarization
The QRS complex represents ventricular depolarization — the electrical event that triggers the ventricles to contract and pump blood. Atrial depolarization is represented by the P wave, and ventricular repolarization is represented by the T wave.
EKG certification Certification EKG Technician Certification 1
Which of the following correctly describes the normal PR interval on an adult EKG?