BASIC ARRHYTHMIA Sentara Test
Questions and Answers Graded A+
SECTION 1: FOUNDATIONS & NORMAL VALUES (Q1-15)
Q1. What are the 5 steps to EKG Interpretation?
• Correct Answer: 1) Look for P waves; 2) Measure PR Interval (PRI); 3)
Measure QRS; 4) Identify Rhythm as regular or irregular; 5) Count Rate
• Rationale: This systematic approach ensures no critical detail is missed. The
QT interval is important to measure as many medications can affect its
duration; however, this does not alter the primary interpretation.
Q2. What is the normal PR interval length?
• Correct Answer: 0.12 - 0.20 seconds
• Rationale: The PR interval represents the time it takes for the electrical
impulse to travel from the sinus node through the atria, AV node, and bundle
of His.
Q3. What is the normal QRS interval length?
• Correct Answer: 0.06 - 0.12 seconds
• Rationale: The QRS complex represents ventricular depolarization. A
"wide" QRS (>0.12 seconds) indicates that the electrical impulse is taking an
abnormal, prolonged pathway through the ventricles (e.g., a PVC or bundle
branch block).
Q4. What is the normal QT interval length?
, • Correct Answer: 0.32 - 0.44 seconds
• Rationale: The QT interval represents the total time for ventricular
depolarization and repolarization. Prolonged QT intervals (often caused by
medications) increase the risk for Torsades de Pointes.
Q5. What is the length of a small square on EKG paper?
• Correct Answer: 0.04 seconds
• Rationale: EKG paper runs at a standard speed of 25 mm/second. Each
small 1 mm box equals 0.04 seconds, while the larger heavy-lined box (5
small boxes) equals 0.20 seconds.
Q6. What is the length of a regular (large) square on EKG paper?
• Correct Answer: 0.2 seconds
• Rationale: The large box is used for rapid heart rate calculations (e.g.,
counting the number of large boxes between R waves to determine rate).
Q7. What does the P wave represent?
• Correct Answer: Atrial depolarization (contraction)
• Rationale: The P wave is generated when the sinus node fires and the
electrical impulse spreads through the right and left atria.
Q8. What does the QRS complex represent?
• Correct Answer: Ventricular depolarization (contraction)
• Rationale: This is the large, tall waveform on the EKG. It represents the
electrical activation of the thick ventricular muscle mass.
Q9. What does QTI (or QT interval) represent?
• Correct Answer: Inherent rate of Purkinje fibers
• Rationale: Specifically, the QT interval reflects the total duration of
ventricular activity, but the backup (escape) pacemaker rate of the Purkinje
Questions and Answers Graded A+
SECTION 1: FOUNDATIONS & NORMAL VALUES (Q1-15)
Q1. What are the 5 steps to EKG Interpretation?
• Correct Answer: 1) Look for P waves; 2) Measure PR Interval (PRI); 3)
Measure QRS; 4) Identify Rhythm as regular or irregular; 5) Count Rate
• Rationale: This systematic approach ensures no critical detail is missed. The
QT interval is important to measure as many medications can affect its
duration; however, this does not alter the primary interpretation.
Q2. What is the normal PR interval length?
• Correct Answer: 0.12 - 0.20 seconds
• Rationale: The PR interval represents the time it takes for the electrical
impulse to travel from the sinus node through the atria, AV node, and bundle
of His.
Q3. What is the normal QRS interval length?
• Correct Answer: 0.06 - 0.12 seconds
• Rationale: The QRS complex represents ventricular depolarization. A
"wide" QRS (>0.12 seconds) indicates that the electrical impulse is taking an
abnormal, prolonged pathway through the ventricles (e.g., a PVC or bundle
branch block).
Q4. What is the normal QT interval length?
, • Correct Answer: 0.32 - 0.44 seconds
• Rationale: The QT interval represents the total time for ventricular
depolarization and repolarization. Prolonged QT intervals (often caused by
medications) increase the risk for Torsades de Pointes.
Q5. What is the length of a small square on EKG paper?
• Correct Answer: 0.04 seconds
• Rationale: EKG paper runs at a standard speed of 25 mm/second. Each
small 1 mm box equals 0.04 seconds, while the larger heavy-lined box (5
small boxes) equals 0.20 seconds.
Q6. What is the length of a regular (large) square on EKG paper?
• Correct Answer: 0.2 seconds
• Rationale: The large box is used for rapid heart rate calculations (e.g.,
counting the number of large boxes between R waves to determine rate).
Q7. What does the P wave represent?
• Correct Answer: Atrial depolarization (contraction)
• Rationale: The P wave is generated when the sinus node fires and the
electrical impulse spreads through the right and left atria.
Q8. What does the QRS complex represent?
• Correct Answer: Ventricular depolarization (contraction)
• Rationale: This is the large, tall waveform on the EKG. It represents the
electrical activation of the thick ventricular muscle mass.
Q9. What does QTI (or QT interval) represent?
• Correct Answer: Inherent rate of Purkinje fibers
• Rationale: Specifically, the QT interval reflects the total duration of
ventricular activity, but the backup (escape) pacemaker rate of the Purkinje
