[HAADECGTech] HAAD ECGTechnician DOH
Licensureination for ECG Technician
Certification Review Guide
**Question 1.** Which cardiac structure initiates the electrical impulse in a normal heart?
A) AV node
B) Bundle of His
C) SA node
D) Purkinje fibers
Answer: C
Explanation: The sinoatrial (SA) node, located in the right atrium, is the natural pacemaker that
generates the impulse initiating each cardiac cycle.
**Question 2.** The P‑wave on an ECG represents:
A) Ventricular depolarization
B) Atrial repolarization
C) Atrial depolarization
D) Ventricular repolarization
Answer: C
Explanation: The P‑wave corresponds to the depolarization of the atria as the impulse spreads
from the SA node through the atrial myocardium.
**Question 3.** In the standard 12‑lead ECG, which lead is placed on the left arm?
A) Lead I
B) aVR
C) aVL
D) Lead III
Answer: C
,[HAADECGTech] HAAD ECGTechnician DOH
Licensureination for ECG Technician
Certification Review Guide
Explanation: aVL is the augmented lead that records the voltage between the left arm electrode
and the average of the right arm and left leg electrodes.
**Question 4.** The normal duration of the PR interval is:
A) 0.06–0.10 seconds
B) 0.12–0.20 seconds
C) 0.20–0.30 seconds
D) 0.30–0.40 seconds
Answer: B
Explanation: A PR interval of 0.12–0.20 seconds reflects normal conduction from the atria
through the AV node to the ventricles.
**Question 5.** Which coronary artery supplies the majority of the left ventricular lateral wall?
A) Right coronary artery (RCA)
B) Left anterior descending (LAD)
C) Circumflex artery (LCx)
D) Posterior descending artery (PDA)
Answer: C
Explanation: The left circumflex artery runs in the left atrioventricular groove and perfuses the
lateral aspect of the left ventricle.
**Question 6.** The standard calibration of an ECG machine is 10 mm/mV. If a QRS complex
measures 5 mm high, what is its voltage amplitude?
A) 0.2 mV
B) 0.5 mV
,[HAADECGTech] HAAD ECGTechnician DOH
Licensureination for ECG Technician
Certification Review Guide
C) 1.0 mV
D) 2.0 mV
Answer: B
Explanation: 5 mm ÷ 10 mm/mV = 0.5 mV.
**Question 7.** Which artifact is most commonly caused by a patient’s tremor?
A) Baseline wander
B) Muscle tremor artifact
C) 60‑Hz interference
D) Lead reversal artifact
Answer: B
Explanation: Muscle tremor creates high‑frequency, irregular fluctuations that appear as a
“shaky” baseline.
**Question 8.** In Einthoven’s triangle, lead II records the potential difference between which
two electrodes?
A) Right arm and left arm
B) Left arm and left leg
C) Right arm and left leg
D) Right leg and left leg
Answer: C
Explanation: Lead II measures the voltage from the right arm (negative) to the left leg (positive)
electrode.
, [HAADECGTech] HAAD ECGTechnician DOH
Licensureination for ECG Technician
Certification Review Guide
**Question 9.** A heart rate calculated using the “300 method” on a regular rhythm gives a
value of 75 bpm. How many large squares separate two consecutive R‑waves?
A) 2
B) 3
C) 4
D) 5
Answer: C
Explanation: 300 ÷ 75 = 4 large squares between R‑waves.
**Question 10.** Which of the following is a characteristic ECG finding of atrial fibrillation?
A) Saw‑tooth flutter waves
B) Regularly spaced P‑waves
C) Irregularly irregular rhythm with absent discrete P‑waves
D) PR interval prolongation >0.20 s
Answer: C
Explanation: A‑fib shows a chaotic atrial activity with no distinct P‑waves and an irregular
ventricular response.
**Question 11.** The QRS complex duration is considered prolonged if it exceeds:
A) 0.06 seconds
B) 0.08 seconds
C) 0.10 seconds
D) 0.12 seconds
Answer: D
Licensureination for ECG Technician
Certification Review Guide
**Question 1.** Which cardiac structure initiates the electrical impulse in a normal heart?
A) AV node
B) Bundle of His
C) SA node
D) Purkinje fibers
Answer: C
Explanation: The sinoatrial (SA) node, located in the right atrium, is the natural pacemaker that
generates the impulse initiating each cardiac cycle.
**Question 2.** The P‑wave on an ECG represents:
A) Ventricular depolarization
B) Atrial repolarization
C) Atrial depolarization
D) Ventricular repolarization
Answer: C
Explanation: The P‑wave corresponds to the depolarization of the atria as the impulse spreads
from the SA node through the atrial myocardium.
**Question 3.** In the standard 12‑lead ECG, which lead is placed on the left arm?
A) Lead I
B) aVR
C) aVL
D) Lead III
Answer: C
,[HAADECGTech] HAAD ECGTechnician DOH
Licensureination for ECG Technician
Certification Review Guide
Explanation: aVL is the augmented lead that records the voltage between the left arm electrode
and the average of the right arm and left leg electrodes.
**Question 4.** The normal duration of the PR interval is:
A) 0.06–0.10 seconds
B) 0.12–0.20 seconds
C) 0.20–0.30 seconds
D) 0.30–0.40 seconds
Answer: B
Explanation: A PR interval of 0.12–0.20 seconds reflects normal conduction from the atria
through the AV node to the ventricles.
**Question 5.** Which coronary artery supplies the majority of the left ventricular lateral wall?
A) Right coronary artery (RCA)
B) Left anterior descending (LAD)
C) Circumflex artery (LCx)
D) Posterior descending artery (PDA)
Answer: C
Explanation: The left circumflex artery runs in the left atrioventricular groove and perfuses the
lateral aspect of the left ventricle.
**Question 6.** The standard calibration of an ECG machine is 10 mm/mV. If a QRS complex
measures 5 mm high, what is its voltage amplitude?
A) 0.2 mV
B) 0.5 mV
,[HAADECGTech] HAAD ECGTechnician DOH
Licensureination for ECG Technician
Certification Review Guide
C) 1.0 mV
D) 2.0 mV
Answer: B
Explanation: 5 mm ÷ 10 mm/mV = 0.5 mV.
**Question 7.** Which artifact is most commonly caused by a patient’s tremor?
A) Baseline wander
B) Muscle tremor artifact
C) 60‑Hz interference
D) Lead reversal artifact
Answer: B
Explanation: Muscle tremor creates high‑frequency, irregular fluctuations that appear as a
“shaky” baseline.
**Question 8.** In Einthoven’s triangle, lead II records the potential difference between which
two electrodes?
A) Right arm and left arm
B) Left arm and left leg
C) Right arm and left leg
D) Right leg and left leg
Answer: C
Explanation: Lead II measures the voltage from the right arm (negative) to the left leg (positive)
electrode.
, [HAADECGTech] HAAD ECGTechnician DOH
Licensureination for ECG Technician
Certification Review Guide
**Question 9.** A heart rate calculated using the “300 method” on a regular rhythm gives a
value of 75 bpm. How many large squares separate two consecutive R‑waves?
A) 2
B) 3
C) 4
D) 5
Answer: C
Explanation: 300 ÷ 75 = 4 large squares between R‑waves.
**Question 10.** Which of the following is a characteristic ECG finding of atrial fibrillation?
A) Saw‑tooth flutter waves
B) Regularly spaced P‑waves
C) Irregularly irregular rhythm with absent discrete P‑waves
D) PR interval prolongation >0.20 s
Answer: C
Explanation: A‑fib shows a chaotic atrial activity with no distinct P‑waves and an irregular
ventricular response.
**Question 11.** The QRS complex duration is considered prolonged if it exceeds:
A) 0.06 seconds
B) 0.08 seconds
C) 0.10 seconds
D) 0.12 seconds
Answer: D
