BASIC ARRHYTHMIA SENTARA TEST – QUESTIONS AND ANSWERS |
VERIFIED AND WELL DETAILED ANSWERS | PLUS RATIONALES |
GUARANTEED PASS | LATEST EXAM UPDATE
Question 1
What is the normal duration of the PR interval on an ECG?
A) 0.04 to 0.12 seconds
B) 0.12 to 0.20 seconds
C) 0.20 to 0.28 seconds
D) 0.28 to 0.36 seconds
Answer
Answer: B
Rationale
The PR interval represents the time from the onset of atrial depolarization to the onset of ventricular
depolarization. A normal PR interval is between 0.12 and 0.20 seconds (3 to 5 small boxes on
standard ECG paper). This interval allows for proper atrial filling of the ventricles before contraction.
Question 2
What is the normal duration of the QRS complex?
A) Less than 0.12 seconds
B) 0.12 to 0.20 seconds
C) 0.20 to 0.28 seconds
D) Greater than 0.28 seconds
Answer
Answer: A
Rationale
The QRS complex represents ventricular depolarization. A normal QRS duration is less than 0.12
seconds (less than 3 small boxes). A QRS duration of 0.12 seconds or greater indicates a conduction
delay or block in the ventricles, such as a bundle branch block or a ventricular rhythm.
,Question 3
How many small boxes on ECG paper equal one second?
A) 5
B) 10
C) 15
D) 25
Answer
Answer: D
Rationale
Standard ECG paper runs at a speed of 25 mm per second. Each small box represents 1 mm, so 25
small boxes equal one second. Each large box (5 small boxes) represents 0.20 seconds, so five large
boxes equal one second. This time scale is essential for accurately measuring intervals and
calculating heart rates.
Question 4
What is the heart rate for a rhythm with a regular R-R interval of 20 small boxes?
A) 60 beats per minute
B) 75 beats per minute
C) 100 beats per minute
D) 150 beats per minute
Answer
Answer: B
Rationale
To calculate heart rate using the 1500 method, divide 1500 by the number of small boxes between R
waves. 1500 ÷ 20 = 75 beats per minute. This method is accurate for regular rhythms and provides a
quick bedside calculation.
Question 5
Which of the following best describes Normal Sinus Rhythm?
2
,A) Rate 60-100, regular, P wave before every QRS, PR 0.12-0.20, QRS <0.12
B) Rate 40-60, regular, inverted P waves, QRS <0.12
C) Rate >100, regular, P waves hidden in T waves
D) Rate 60-100, irregular, no P waves, QRS <0.12
Answer
Answer: A
Rationale
Normal Sinus Rhythm originates from the sinoatrial node and is the normal pacemaker of the heart. It
is characterized by a regular rhythm, a rate between 60 and 100 beats per minute, a P wave preceding
every QRS complex, a PR interval of 0.12 to 0.20 seconds, and a QRS duration of less than 0.12
seconds.
Question 6
A patient's rhythm strip shows a regular rhythm with a rate of 48 beats per minute, a normal P
wave before each QRS, PR interval of 0.16 seconds, and QRS of 0.08 seconds. What is this
rhythm?
A) Normal Sinus Rhythm
B) Sinus Bradycardia
C) Sinus Tachycardia
D) Junctional Rhythm
Answer
Answer: B
Rationale
Sinus bradycardia has all the characteristics of normal sinus rhythm except the rate is less than 60
beats per minute. The SA node is still the pacemaker, so P waves are present and normal, and the PR
and QRS intervals are within normal limits.
Question 7
A patient presents with a heart rate of 130 beats per minute, regular rhythm, normal P waves
before each QRS, PR 0.14 seconds, and QRS 0.08 seconds. What is the most likely rhythm?
A) Sinus Bradycardia
3
, B) Sinus Tachycardia
C) Atrial Flutter
D) Ventricular Tachycardia
Answer
Answer: B
Rationale
Sinus tachycardia is characterized by a regular rhythm originating from the SA node with a rate greater
than 100 beats per minute. The P waves are normal and precede each QRS, and the PR and QRS
intervals are within normal limits. It is often a physiological response to exercise, pain, fever, or stress.
Question 8
What is the primary characteristic that distinguishes Sinus Arrhythmia from other sinus
rhythms?
A) The rate is always below 60
B) The rate varies with the respiratory cycle
C) The P waves are inverted
D) The QRS is wide
Answer
Answer: B
Rationale
Sinus arrhythmia is a normal variant of sinus rhythm where the heart rate increases with inspiration
and decreases with expiration. The rhythm is irregular but follows a cyclical pattern tied to breathing.
The P waves, PR interval, and QRS complex are otherwise normal.
Question 9
What is a key characteristic of a Premature Atrial Contraction (PAC)?
A) A wide, bizarre QRS complex
B) An early beat with a P wave that may be hidden in the preceding T wave
C) A compensatory pause that is typically fully compensatory
D) Absence of a P wave before the beat
4
VERIFIED AND WELL DETAILED ANSWERS | PLUS RATIONALES |
GUARANTEED PASS | LATEST EXAM UPDATE
Question 1
What is the normal duration of the PR interval on an ECG?
A) 0.04 to 0.12 seconds
B) 0.12 to 0.20 seconds
C) 0.20 to 0.28 seconds
D) 0.28 to 0.36 seconds
Answer
Answer: B
Rationale
The PR interval represents the time from the onset of atrial depolarization to the onset of ventricular
depolarization. A normal PR interval is between 0.12 and 0.20 seconds (3 to 5 small boxes on
standard ECG paper). This interval allows for proper atrial filling of the ventricles before contraction.
Question 2
What is the normal duration of the QRS complex?
A) Less than 0.12 seconds
B) 0.12 to 0.20 seconds
C) 0.20 to 0.28 seconds
D) Greater than 0.28 seconds
Answer
Answer: A
Rationale
The QRS complex represents ventricular depolarization. A normal QRS duration is less than 0.12
seconds (less than 3 small boxes). A QRS duration of 0.12 seconds or greater indicates a conduction
delay or block in the ventricles, such as a bundle branch block or a ventricular rhythm.
,Question 3
How many small boxes on ECG paper equal one second?
A) 5
B) 10
C) 15
D) 25
Answer
Answer: D
Rationale
Standard ECG paper runs at a speed of 25 mm per second. Each small box represents 1 mm, so 25
small boxes equal one second. Each large box (5 small boxes) represents 0.20 seconds, so five large
boxes equal one second. This time scale is essential for accurately measuring intervals and
calculating heart rates.
Question 4
What is the heart rate for a rhythm with a regular R-R interval of 20 small boxes?
A) 60 beats per minute
B) 75 beats per minute
C) 100 beats per minute
D) 150 beats per minute
Answer
Answer: B
Rationale
To calculate heart rate using the 1500 method, divide 1500 by the number of small boxes between R
waves. 1500 ÷ 20 = 75 beats per minute. This method is accurate for regular rhythms and provides a
quick bedside calculation.
Question 5
Which of the following best describes Normal Sinus Rhythm?
2
,A) Rate 60-100, regular, P wave before every QRS, PR 0.12-0.20, QRS <0.12
B) Rate 40-60, regular, inverted P waves, QRS <0.12
C) Rate >100, regular, P waves hidden in T waves
D) Rate 60-100, irregular, no P waves, QRS <0.12
Answer
Answer: A
Rationale
Normal Sinus Rhythm originates from the sinoatrial node and is the normal pacemaker of the heart. It
is characterized by a regular rhythm, a rate between 60 and 100 beats per minute, a P wave preceding
every QRS complex, a PR interval of 0.12 to 0.20 seconds, and a QRS duration of less than 0.12
seconds.
Question 6
A patient's rhythm strip shows a regular rhythm with a rate of 48 beats per minute, a normal P
wave before each QRS, PR interval of 0.16 seconds, and QRS of 0.08 seconds. What is this
rhythm?
A) Normal Sinus Rhythm
B) Sinus Bradycardia
C) Sinus Tachycardia
D) Junctional Rhythm
Answer
Answer: B
Rationale
Sinus bradycardia has all the characteristics of normal sinus rhythm except the rate is less than 60
beats per minute. The SA node is still the pacemaker, so P waves are present and normal, and the PR
and QRS intervals are within normal limits.
Question 7
A patient presents with a heart rate of 130 beats per minute, regular rhythm, normal P waves
before each QRS, PR 0.14 seconds, and QRS 0.08 seconds. What is the most likely rhythm?
A) Sinus Bradycardia
3
, B) Sinus Tachycardia
C) Atrial Flutter
D) Ventricular Tachycardia
Answer
Answer: B
Rationale
Sinus tachycardia is characterized by a regular rhythm originating from the SA node with a rate greater
than 100 beats per minute. The P waves are normal and precede each QRS, and the PR and QRS
intervals are within normal limits. It is often a physiological response to exercise, pain, fever, or stress.
Question 8
What is the primary characteristic that distinguishes Sinus Arrhythmia from other sinus
rhythms?
A) The rate is always below 60
B) The rate varies with the respiratory cycle
C) The P waves are inverted
D) The QRS is wide
Answer
Answer: B
Rationale
Sinus arrhythmia is a normal variant of sinus rhythm where the heart rate increases with inspiration
and decreases with expiration. The rhythm is irregular but follows a cyclical pattern tied to breathing.
The P waves, PR interval, and QRS complex are otherwise normal.
Question 9
What is a key characteristic of a Premature Atrial Contraction (PAC)?
A) A wide, bizarre QRS complex
B) An early beat with a P wave that may be hidden in the preceding T wave
C) A compensatory pause that is typically fully compensatory
D) Absence of a P wave before the beat
4
