EKG CLEP Test Exam 2 QUESTIONS AND
CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2025
1. What does the P wave represent in an EKG?
• A. Ventricular depolarization
• B. Atrial depolarization
• C. Atrial repolarization
• D. Ventricular repolarization
The P wave reflects the electrical activity associated with the
depolarization of the atria, which leads to atrial contraction.
2. The QRS complex duration normally lasts:
• A. Less than 0.04 seconds
• B. 0.20 to 0.24 seconds
• C. 0.06 to 0.10 seconds
,• D. Greater than 0.12 seconds
A normal QRS complex should be narrow, typically between 0.06 and
0.10 seconds, indicating efficient ventricular conduction.
3. What part of the conduction system delays the electrical impulse to
allow for atrial contraction?
• A. Sinoatrial (SA) node
• B. Atrioventricular (AV) node
• C. Purkinje fibers
• D. Bundle of His
The AV node slows the impulse to ensure the atria have time to fully
contract and empty into the ventricles before ventricular contraction.
4. Which rhythm is characterized by no discernible P waves and
irregularly irregular QRS complexes?
• A. Atrial flutter
• B. Atrial fibrillation
• C. Ventricular tachycardia
• D. Sinus tachycardia
Atrial fibrillation produces chaotic electrical activity in the atria,
causing an irregularly irregular rhythm without clear P waves.
5. What is the heart’s natural pacemaker?
• A. AV node
,• B. SA node
• C. Bundle of His
• D. Left bundle branch
The SA node initiates electrical impulses in the heart, making it the
primary pacemaker.
6. Which electrolyte imbalance is most likely to cause peaked T waves on
an EKG?
• A. Hypokalemia
• B. Hyperkalemia
• C. Hypocalcemia
• D. Hypernatremia
Excess potassium in the blood affects repolarization, leading to tall,
peaked T waves.
7. What does a prolonged QT interval indicate?
• A. Early ventricular depolarization
• B. Early atrial contraction
• C. Delayed ventricular repolarization
• D. Rapid atrial repolarization
A prolonged QT interval reflects delayed repolarization, increasing
the risk for torsades de pointes and other arrhythmias.
8. In which lead is the QRS complex normally upright?
, • A. aVR
• B. V1
• C. Lead II
• D. V6
Lead II is aligned with the general direction of the heart's electrical
axis, so the QRS complex is typically upright.
9. What is the rate range for sinus bradycardia?
• A. 100–150 bpm
• B. 60–100 bpm
• C. Less than 60 bpm
• D. Over 150 bpm
Sinus bradycardia is defined as a regular rhythm originating from the
SA node with a rate under 60 bpm.
10. Which rhythm requires immediate defibrillation?
• A. Sinus tachycardia
• B. Atrial flutter
• C. Ventricular fibrillation
• D. First-degree AV block
Ventricular fibrillation is a life-threatening rhythm requiring
immediate defibrillation to restore cardiac output.
CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2025
1. What does the P wave represent in an EKG?
• A. Ventricular depolarization
• B. Atrial depolarization
• C. Atrial repolarization
• D. Ventricular repolarization
The P wave reflects the electrical activity associated with the
depolarization of the atria, which leads to atrial contraction.
2. The QRS complex duration normally lasts:
• A. Less than 0.04 seconds
• B. 0.20 to 0.24 seconds
• C. 0.06 to 0.10 seconds
,• D. Greater than 0.12 seconds
A normal QRS complex should be narrow, typically between 0.06 and
0.10 seconds, indicating efficient ventricular conduction.
3. What part of the conduction system delays the electrical impulse to
allow for atrial contraction?
• A. Sinoatrial (SA) node
• B. Atrioventricular (AV) node
• C. Purkinje fibers
• D. Bundle of His
The AV node slows the impulse to ensure the atria have time to fully
contract and empty into the ventricles before ventricular contraction.
4. Which rhythm is characterized by no discernible P waves and
irregularly irregular QRS complexes?
• A. Atrial flutter
• B. Atrial fibrillation
• C. Ventricular tachycardia
• D. Sinus tachycardia
Atrial fibrillation produces chaotic electrical activity in the atria,
causing an irregularly irregular rhythm without clear P waves.
5. What is the heart’s natural pacemaker?
• A. AV node
,• B. SA node
• C. Bundle of His
• D. Left bundle branch
The SA node initiates electrical impulses in the heart, making it the
primary pacemaker.
6. Which electrolyte imbalance is most likely to cause peaked T waves on
an EKG?
• A. Hypokalemia
• B. Hyperkalemia
• C. Hypocalcemia
• D. Hypernatremia
Excess potassium in the blood affects repolarization, leading to tall,
peaked T waves.
7. What does a prolonged QT interval indicate?
• A. Early ventricular depolarization
• B. Early atrial contraction
• C. Delayed ventricular repolarization
• D. Rapid atrial repolarization
A prolonged QT interval reflects delayed repolarization, increasing
the risk for torsades de pointes and other arrhythmias.
8. In which lead is the QRS complex normally upright?
, • A. aVR
• B. V1
• C. Lead II
• D. V6
Lead II is aligned with the general direction of the heart's electrical
axis, so the QRS complex is typically upright.
9. What is the rate range for sinus bradycardia?
• A. 100–150 bpm
• B. 60–100 bpm
• C. Less than 60 bpm
• D. Over 150 bpm
Sinus bradycardia is defined as a regular rhythm originating from the
SA node with a rate under 60 bpm.
10. Which rhythm requires immediate defibrillation?
• A. Sinus tachycardia
• B. Atrial flutter
• C. Ventricular fibrillation
• D. First-degree AV block
Ventricular fibrillation is a life-threatening rhythm requiring
immediate defibrillation to restore cardiac output.
