UCLA EKG TEST PAPER 2026 QUESTIONS &
VERIFIED ANSWERS | COMPLETE ECG
INTERPRETATION STUDY GUIDE | CARDIAC
RHYTHMS, ARRHYTHMIAS & CLINICAL
PRACTICE TEST | GRADED A+ GUARANTEED
PASS
UCLA EKG TEST PAPER
QUESTIONS & VERIFIED ANSWERS | COMPLETE ECG INTERPRETATION STUDY
GUIDE
CARDIAC RHYTHMS, ARRHYTHMIAS & CLINICAL PRACTICE TEST | GRADED A+
SECTION 1: BASIC ECG CONCEPTS & FUNDAMENTALS (Q1–Q50)
Q1. What does the P wave represent on an ECG?
A. Ventricular depolarization B. Ventricular repolarization C. AV node conduction delay
D. Atrial depolarization E. Bundle of His activation
CORRECT ANSWER: D — Atrial depolarization RATIONALE: The P wave
reflects the electrical activation (depolarization) of both atria as the impulse travels from
the SA node through atrial tissue.
Q2. What does the QRS complex represent?
A. Atrial repolarization B. SA node firing C. Ventricular depolarization D.
Ventricular repolarization E. AV nodal delay
CORRECT ANSWER: C — Ventricular depolarization RATIONALE: The QRS
complex represents the rapid depolarization of the ventricular myocardium, which
triggers mechanical contraction of the ventricles.
Q3. What does the T wave represent?
,A. Atrial depolarization B. Atrial repolarization C. Ventricular depolarization D.
Ventricular repolarization E. SA node recovery
CORRECT ANSWER: D — Ventricular repolarization RATIONALE: The T
wave represents recovery (repolarization) of the ventricular myocardium as cells return
to their resting membrane potential.
Q4. What is the normal duration of the PR interval?
A. 0.06–0.10 seconds B. 0.12–0.20 seconds C. 0.20–0.30 seconds D. 0.08–0.12
seconds E. 0.30–0.40 seconds
CORRECT ANSWER: B — 0.12–0.20 seconds RATIONALE: The PR interval
measures AV node conduction time. Normal range is 0.12–0.20 seconds (3–5 small
squares on standard ECG paper).
Q5. What is the normal duration of the QRS complex?
A. Less than 0.12 seconds B. 0.12–0.20 seconds C. 0.20–0.28 seconds D. 0.10–
0.15 seconds E. Less than 0.08 seconds
CORRECT ANSWER: A — Less than 0.12 seconds RATIONALE: A normal
QRS duration is less than 0.12 seconds (3 small squares). Widening beyond this
suggests bundle branch block or ventricular origin.
Q6. Standard ECG paper runs at what speed?
A. 10 mm/sec B. 15 mm/sec C. 20 mm/sec D. 25 mm/sec E. 50 mm/sec
CORRECT ANSWER: D — 25 mm/sec RATIONALE: Standard ECG paper
speed is 25 mm/sec. Each small square = 0.04 sec; each large square = 0.20 sec.
Q7. On standard ECG paper, one large square equals how many seconds?
A. 0.04 seconds B. 0.08 seconds C. 0.10 seconds D. 0.20 seconds E. 0.40
seconds
, CORRECT ANSWER: D — 0.20 seconds RATIONALE: Each large square on
ECG paper = 5 small squares × 0.04 sec = 0.20 seconds at standard paper speed of 25
mm/sec.
Q8. What is the amplitude of a standard ECG calibration signal?
A. 5 mm B. 10 mm C. 15 mm D. 20 mm E. 1 mm
CORRECT ANSWER: B — 10 mm RATIONALE: Standard ECG calibration is 1
mV = 10 mm (1 cm). This ensures consistent amplitude interpretation across all ECG
machines.
Q9. Which lead is considered the most important single lead for rhythm
monitoring?
A. Lead I B. Lead aVF C. Lead II D. Lead V1 E. Lead aVR
CORRECT ANSWER: C — Lead II RATIONALE: Lead II runs parallel to the
mean electrical axis of the heart and provides the clearest view of P waves and QRS
morphology, making it ideal for rhythm monitoring.
Q10. The isoelectric line on an ECG represents:
A. Maximal depolarization B. Peak of ventricular contraction C. No electrical
activity / baseline D. Atrial repolarization E. Refractory period
CORRECT ANSWER: C — No electrical activity / baseline RATIONALE: The
isoelectric (baseline) line represents periods of no net electrical activity, such as the TP
segment between beats.
Q11. What does the ST segment represent?
A. Atrial depolarization B. Ventricular depolarization C. Period between ventricular
depolarization and repolarization D. AV node delay E. Bundle branch conduction
CORRECT ANSWER: C — Period between ventricular depolarization and
repolarization RATIONALE: The ST segment corresponds to the plateau phase of
the ventricular action potential, when all ventricular cells are depolarized. Elevation or
depression here is clinically significant.
, Q12. The QT interval represents:
A. Only ventricular depolarization B. Only ventricular repolarization C. Total
ventricular electrical activity (depolarization + repolarization) D. Atrial
depolarization and repolarization E. AV nodal conduction time
CORRECT ANSWER: C — Total ventricular electrical activity (depolarization +
repolarization) RATIONALE: The QT interval spans from the start of the QRS
complex to the end of the T wave, encompassing the entire duration of ventricular
electrical activity.
Q13. What is the normal corrected QT interval (QTc) in adults?
A. Less than 0.30 seconds B. Less than 0.44 seconds C. Less than 0.50 seconds
D. 0.44–0.50 seconds E. Less than 0.36 seconds
CORRECT ANSWER: B — Less than 0.44 seconds RATIONALE: QTc
(corrected for heart rate using Bazett's formula) should be <0.44 sec in men and <0.46
sec in women. Prolongation increases the risk of Torsades de Pointes.
Q14. Which formula is most commonly used to calculate corrected QT interval?
A. Fridericia formula B. Bazett's formula C. Hodges formula D. Framingham
formula E. Rautaharju formula
CORRECT ANSWER: B — Bazett's formula RATIONALE: Bazett's formula:
QTc = QT / √RR interval. It is the most widely used correction formula despite being less
accurate at extreme heart rates.
Q15. The normal heart rate range on ECG is:
A. 40–60 bpm B. 60–80 bpm C. 60–100 bpm D. 80–120 bpm E. 50–90 bpm
CORRECT ANSWER: C — 60–100 bpm RATIONALE: Normal sinus rhythm
has a rate of 60–100 bpm. Below 60 is bradycardia; above 100 is tachycardia.
Q16. To calculate heart rate using the 300 method, you divide 300 by:
VERIFIED ANSWERS | COMPLETE ECG
INTERPRETATION STUDY GUIDE | CARDIAC
RHYTHMS, ARRHYTHMIAS & CLINICAL
PRACTICE TEST | GRADED A+ GUARANTEED
PASS
UCLA EKG TEST PAPER
QUESTIONS & VERIFIED ANSWERS | COMPLETE ECG INTERPRETATION STUDY
GUIDE
CARDIAC RHYTHMS, ARRHYTHMIAS & CLINICAL PRACTICE TEST | GRADED A+
SECTION 1: BASIC ECG CONCEPTS & FUNDAMENTALS (Q1–Q50)
Q1. What does the P wave represent on an ECG?
A. Ventricular depolarization B. Ventricular repolarization C. AV node conduction delay
D. Atrial depolarization E. Bundle of His activation
CORRECT ANSWER: D — Atrial depolarization RATIONALE: The P wave
reflects the electrical activation (depolarization) of both atria as the impulse travels from
the SA node through atrial tissue.
Q2. What does the QRS complex represent?
A. Atrial repolarization B. SA node firing C. Ventricular depolarization D.
Ventricular repolarization E. AV nodal delay
CORRECT ANSWER: C — Ventricular depolarization RATIONALE: The QRS
complex represents the rapid depolarization of the ventricular myocardium, which
triggers mechanical contraction of the ventricles.
Q3. What does the T wave represent?
,A. Atrial depolarization B. Atrial repolarization C. Ventricular depolarization D.
Ventricular repolarization E. SA node recovery
CORRECT ANSWER: D — Ventricular repolarization RATIONALE: The T
wave represents recovery (repolarization) of the ventricular myocardium as cells return
to their resting membrane potential.
Q4. What is the normal duration of the PR interval?
A. 0.06–0.10 seconds B. 0.12–0.20 seconds C. 0.20–0.30 seconds D. 0.08–0.12
seconds E. 0.30–0.40 seconds
CORRECT ANSWER: B — 0.12–0.20 seconds RATIONALE: The PR interval
measures AV node conduction time. Normal range is 0.12–0.20 seconds (3–5 small
squares on standard ECG paper).
Q5. What is the normal duration of the QRS complex?
A. Less than 0.12 seconds B. 0.12–0.20 seconds C. 0.20–0.28 seconds D. 0.10–
0.15 seconds E. Less than 0.08 seconds
CORRECT ANSWER: A — Less than 0.12 seconds RATIONALE: A normal
QRS duration is less than 0.12 seconds (3 small squares). Widening beyond this
suggests bundle branch block or ventricular origin.
Q6. Standard ECG paper runs at what speed?
A. 10 mm/sec B. 15 mm/sec C. 20 mm/sec D. 25 mm/sec E. 50 mm/sec
CORRECT ANSWER: D — 25 mm/sec RATIONALE: Standard ECG paper
speed is 25 mm/sec. Each small square = 0.04 sec; each large square = 0.20 sec.
Q7. On standard ECG paper, one large square equals how many seconds?
A. 0.04 seconds B. 0.08 seconds C. 0.10 seconds D. 0.20 seconds E. 0.40
seconds
, CORRECT ANSWER: D — 0.20 seconds RATIONALE: Each large square on
ECG paper = 5 small squares × 0.04 sec = 0.20 seconds at standard paper speed of 25
mm/sec.
Q8. What is the amplitude of a standard ECG calibration signal?
A. 5 mm B. 10 mm C. 15 mm D. 20 mm E. 1 mm
CORRECT ANSWER: B — 10 mm RATIONALE: Standard ECG calibration is 1
mV = 10 mm (1 cm). This ensures consistent amplitude interpretation across all ECG
machines.
Q9. Which lead is considered the most important single lead for rhythm
monitoring?
A. Lead I B. Lead aVF C. Lead II D. Lead V1 E. Lead aVR
CORRECT ANSWER: C — Lead II RATIONALE: Lead II runs parallel to the
mean electrical axis of the heart and provides the clearest view of P waves and QRS
morphology, making it ideal for rhythm monitoring.
Q10. The isoelectric line on an ECG represents:
A. Maximal depolarization B. Peak of ventricular contraction C. No electrical
activity / baseline D. Atrial repolarization E. Refractory period
CORRECT ANSWER: C — No electrical activity / baseline RATIONALE: The
isoelectric (baseline) line represents periods of no net electrical activity, such as the TP
segment between beats.
Q11. What does the ST segment represent?
A. Atrial depolarization B. Ventricular depolarization C. Period between ventricular
depolarization and repolarization D. AV node delay E. Bundle branch conduction
CORRECT ANSWER: C — Period between ventricular depolarization and
repolarization RATIONALE: The ST segment corresponds to the plateau phase of
the ventricular action potential, when all ventricular cells are depolarized. Elevation or
depression here is clinically significant.
, Q12. The QT interval represents:
A. Only ventricular depolarization B. Only ventricular repolarization C. Total
ventricular electrical activity (depolarization + repolarization) D. Atrial
depolarization and repolarization E. AV nodal conduction time
CORRECT ANSWER: C — Total ventricular electrical activity (depolarization +
repolarization) RATIONALE: The QT interval spans from the start of the QRS
complex to the end of the T wave, encompassing the entire duration of ventricular
electrical activity.
Q13. What is the normal corrected QT interval (QTc) in adults?
A. Less than 0.30 seconds B. Less than 0.44 seconds C. Less than 0.50 seconds
D. 0.44–0.50 seconds E. Less than 0.36 seconds
CORRECT ANSWER: B — Less than 0.44 seconds RATIONALE: QTc
(corrected for heart rate using Bazett's formula) should be <0.44 sec in men and <0.46
sec in women. Prolongation increases the risk of Torsades de Pointes.
Q14. Which formula is most commonly used to calculate corrected QT interval?
A. Fridericia formula B. Bazett's formula C. Hodges formula D. Framingham
formula E. Rautaharju formula
CORRECT ANSWER: B — Bazett's formula RATIONALE: Bazett's formula:
QTc = QT / √RR interval. It is the most widely used correction formula despite being less
accurate at extreme heart rates.
Q15. The normal heart rate range on ECG is:
A. 40–60 bpm B. 60–80 bpm C. 60–100 bpm D. 80–120 bpm E. 50–90 bpm
CORRECT ANSWER: C — 60–100 bpm RATIONALE: Normal sinus rhythm
has a rate of 60–100 bpm. Below 60 is bradycardia; above 100 is tachycardia.
Q16. To calculate heart rate using the 300 method, you divide 300 by:
