BSMH Advanced Arrhythmia Exam — 100
Practice Questions with Answers
Section 1: Cardiac Anatomy,
Electrophysiology & Conduction System (Q1–
20)
1. Which structure serves as the primary pacemaker of the heart under normal
conditions?
A) The atrioventricular node
B) The sinoatrial node
C) The bundle of His
D) The Purkinje fibers
Answer: B
Rationale: The sinoatrial node, located in the right atrium near the superior vena cava,
normally initiates electrical impulses at a rate of 60 to 100 beats per minute, making it the
primary pacemaker of the heart .
2. Which sequence correctly describes the normal path of electrical impulse conduction
through the heart?
A) AV node, SA node, bundle of His, Purkinje fibers, bundle branches
B) SA node, AV node, bundle of His, bundle branches, Purkinje fibers
C) SA node, bundle of His, AV node, bundle branches, Purkinje fibers
D) AV node, bundle of His, SA node, Purkinje fibers, bundle branches
Answer: B
Rationale: The normal conduction pathway begins at the sinoatrial node, travels to the
atrioventricular node where it is delayed, then proceeds through the bundle of His, into the
right and left bundle branches, and finally through the Purkinje fibers to depolarize the
ventricles .
3. During phase 0 of the cardiac action potential in ventricular muscle cells, which ion is
primarily responsible for rapid depolarization?
A) Potassium efflux
B) Sodium influx
,C) Calcium influx
D) Chloride influx
Answer: B
Rationale: Phase 0 of the ventricular muscle action potential is characterized by rapid
depolarization caused by the opening of fast sodium channels and the subsequent influx of
sodium ions into the cell .
4. The PR interval delay occurs primarily at which anatomic structure to allow for
ventricular filling?
A) The sinoatrial node
B) The atrioventricular node
C) The bundle of His
D) The Purkinje fiber network
Answer: B
Rationale: The atrioventricular node conducts impulses more slowly than other cardiac
tissue, creating the PR interval delay. This physiologic delay allows time for atrial contraction
to complete ventricular filling before ventricular depolarization occurs .
5. Which autonomic nervous system influence increases the rate of phase 4 depolarization
in sinoatrial nodal cells, thereby increasing heart rate?
A) Parasympathetic stimulation via acetylcholine
B) Sympathetic stimulation via norepinephrine
C) Vagal stimulation via muscarinic receptors
D) Parasympathetic withdrawal alone
Answer: B
Rationale: Sympathetic stimulation releases norepinephrine, which binds to beta-1
adrenergic receptors on SA nodal cells. This increases the slope of phase 4 depolarization,
resulting in faster spontaneous firing and an increased heart rate .
6. What are the inherent rates of the SA node, AV node, and ventricles respectively?
A) SA = 40-60, AV = 60-100, Ventricle = 20-40
B) SA = 60-100, AV = 40-60, Ventricle = 20-40
C) SA = 60-100, AV = 20-40, Ventricle = 40-60
D) SA = 100-150, AV = 60-100, Ventricle = 40-60
Answer: B
Rationale: The SA node has an inherent rate of 60-100 bpm, the AV node 40-60 bpm, and
the ventricles 20-40 bpm .
, 7. On an ECG strip, how many seconds does one small box represent?
A) 0.04 seconds
B) 0.08 seconds
C) 0.12 seconds
D) 0.20 seconds
Answer: A
Rationale: Each small box on standard ECG paper represents 0.04 seconds at a paper speed
of 25 mm per second. Five small boxes make one large box, which equals 0.20 seconds .
8. One large box on ECG paper equals how many seconds?
A) 0.04 seconds
B) 0.08 seconds
C) 0.12 seconds
D) 0.20 seconds
Answer: D
Rationale: One large box (5 small boxes) equals 0.20 seconds .
9. The P wave on an ECG represents:
A) Ventricular depolarization
B) Atrial depolarization
C) Ventricular repolarization
D) Atrial repolarization
Answer: B
Rationale: The P wave corresponds to atrial depolarization .
10. The QRS interval represents:
A) Atrial depolarization
B) Ventricular depolarization
C) Ventricular repolarization
D) Atrial repolarization
Answer: B
Rationale: The QRS interval represents ventricular depolarization and is normally less than
0.12 seconds .
11. The T wave represents:
A) Ventricular depolarization
B) Atrial repolarization
Practice Questions with Answers
Section 1: Cardiac Anatomy,
Electrophysiology & Conduction System (Q1–
20)
1. Which structure serves as the primary pacemaker of the heart under normal
conditions?
A) The atrioventricular node
B) The sinoatrial node
C) The bundle of His
D) The Purkinje fibers
Answer: B
Rationale: The sinoatrial node, located in the right atrium near the superior vena cava,
normally initiates electrical impulses at a rate of 60 to 100 beats per minute, making it the
primary pacemaker of the heart .
2. Which sequence correctly describes the normal path of electrical impulse conduction
through the heart?
A) AV node, SA node, bundle of His, Purkinje fibers, bundle branches
B) SA node, AV node, bundle of His, bundle branches, Purkinje fibers
C) SA node, bundle of His, AV node, bundle branches, Purkinje fibers
D) AV node, bundle of His, SA node, Purkinje fibers, bundle branches
Answer: B
Rationale: The normal conduction pathway begins at the sinoatrial node, travels to the
atrioventricular node where it is delayed, then proceeds through the bundle of His, into the
right and left bundle branches, and finally through the Purkinje fibers to depolarize the
ventricles .
3. During phase 0 of the cardiac action potential in ventricular muscle cells, which ion is
primarily responsible for rapid depolarization?
A) Potassium efflux
B) Sodium influx
,C) Calcium influx
D) Chloride influx
Answer: B
Rationale: Phase 0 of the ventricular muscle action potential is characterized by rapid
depolarization caused by the opening of fast sodium channels and the subsequent influx of
sodium ions into the cell .
4. The PR interval delay occurs primarily at which anatomic structure to allow for
ventricular filling?
A) The sinoatrial node
B) The atrioventricular node
C) The bundle of His
D) The Purkinje fiber network
Answer: B
Rationale: The atrioventricular node conducts impulses more slowly than other cardiac
tissue, creating the PR interval delay. This physiologic delay allows time for atrial contraction
to complete ventricular filling before ventricular depolarization occurs .
5. Which autonomic nervous system influence increases the rate of phase 4 depolarization
in sinoatrial nodal cells, thereby increasing heart rate?
A) Parasympathetic stimulation via acetylcholine
B) Sympathetic stimulation via norepinephrine
C) Vagal stimulation via muscarinic receptors
D) Parasympathetic withdrawal alone
Answer: B
Rationale: Sympathetic stimulation releases norepinephrine, which binds to beta-1
adrenergic receptors on SA nodal cells. This increases the slope of phase 4 depolarization,
resulting in faster spontaneous firing and an increased heart rate .
6. What are the inherent rates of the SA node, AV node, and ventricles respectively?
A) SA = 40-60, AV = 60-100, Ventricle = 20-40
B) SA = 60-100, AV = 40-60, Ventricle = 20-40
C) SA = 60-100, AV = 20-40, Ventricle = 40-60
D) SA = 100-150, AV = 60-100, Ventricle = 40-60
Answer: B
Rationale: The SA node has an inherent rate of 60-100 bpm, the AV node 40-60 bpm, and
the ventricles 20-40 bpm .
, 7. On an ECG strip, how many seconds does one small box represent?
A) 0.04 seconds
B) 0.08 seconds
C) 0.12 seconds
D) 0.20 seconds
Answer: A
Rationale: Each small box on standard ECG paper represents 0.04 seconds at a paper speed
of 25 mm per second. Five small boxes make one large box, which equals 0.20 seconds .
8. One large box on ECG paper equals how many seconds?
A) 0.04 seconds
B) 0.08 seconds
C) 0.12 seconds
D) 0.20 seconds
Answer: D
Rationale: One large box (5 small boxes) equals 0.20 seconds .
9. The P wave on an ECG represents:
A) Ventricular depolarization
B) Atrial depolarization
C) Ventricular repolarization
D) Atrial repolarization
Answer: B
Rationale: The P wave corresponds to atrial depolarization .
10. The QRS interval represents:
A) Atrial depolarization
B) Ventricular depolarization
C) Ventricular repolarization
D) Atrial repolarization
Answer: B
Rationale: The QRS interval represents ventricular depolarization and is normally less than
0.12 seconds .
11. The T wave represents:
A) Ventricular depolarization
B) Atrial repolarization
