ECG Workout: Exercises in Arrhythmia
Interpretation, 8th Edition by Jane Huff | Original
Test Bank-S
1. Which structure is the primary pacemaker of the heart, initiating the electrical impulse that
produces the P wave?
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node
C. Bundle of His
D. Purkinje fibers
Answer: B
Rationale: The SA node, located in the upper right atrium, has the highest automaticity and normally
initiates the electrical impulse, resulting in atrial depolarization (the P wave). The AV node delays the
impulse, while the Bundle of His and Purkinje fibers conduct it to the ventricles.
2. The PR interval represents the time required for the electrical impulse to travel from the:
A. SA node to the atrial myocardium
B. AV node to the Purkinje fibers
C. Atria through the AV node to the ventricles
D. Ventricles to repolarize
Answer: C
Rationale: The PR interval measures the time from the beginning of atrial depolarization to the
beginning of ventricular depolarization. This includes the delay at the AV node, which allows the
ventricles time to fill.
3. Which heart layer is the thickest and responsible for the forceful contraction of the heart?
A. Epicardium
B. Endocardium
C. Myocardium
,D. Pericardium
Answer: C
Rationale: The myocardium is the middle, muscular layer of the heart wall. It contains the contractile
muscle fibers (cardiomyocytes) that generate the force necessary to pump blood.
4. Blood flow from the right ventricle travels through which valve to reach the lungs?
A. Mitral valve
B. Aortic valve
C. Pulmonic valve
D. Tricuspid valve
Answer: C
Rationale: The right ventricle pumps deoxygenated blood through the pulmonic (pulmonary) valve
into the pulmonary artery, which leads to the lungs for gas exchange.
5. Which coronary artery is most commonly occluded, often leading to significant anterior wall
myocardial infarction?
A. Right coronary artery (RCA)
B. Left anterior descending (LAD) artery
C. Circumflex artery
D. Posterior descending artery
Answer: B
Rationale: The LAD supplies the anterior wall of the left ventricle and the anterior portion of the
ventricular septum. Occlusion here is common and often referred to as the "widow-maker" due to
the large area of myocardium at risk.
6. Which surface of the heart is the apex located against?
A. The diaphragm
B. The sternum
C. The left lung
D. The vertebral column
,Answer: A
Rationale: The apex (the pointed inferior tip of the left ventricle) rests on the diaphragm. This is why
it is often palpated at the 5th intercostal space, midclavicular line.
7. During which phase of the cardiac cycle do the coronary arteries primarily receive blood flow?
A. Ventricular systole
B. Ventricular diastole
C. Atrial systole
D. Isovolumetric contraction
Answer: B
Rationale: During ventricular contraction (systole), the myocardium compresses the coronary
arteries, restricting flow. The coronary arteries fill primarily during ventricular relaxation (diastole)
when the myocardium is relaxed.
8. Which structure delays the electrical impulse to allow for ventricular filling?
A. SA node
B. AV node
C. Bundle branches
D. Purkinje network
Answer: B
Rationale: The AV node intentionally slows conduction (creating the PR segment). This delay ensures
the atria have time to contract and empty blood into the ventricles before the ventricles contract.
9. The systemic circuit begins in which chamber of the heart?
A. Right atrium
B. Right ventricle
C. Left atrium
D. Left ventricle
, Answer: D
Rationale: The left ventricle pumps oxygenated blood into the aorta to begin the high-pressure
systemic circuit, delivering blood to the body tissues.
10. What is the normal resting heart rate for a healthy adult?
A. 40-60 bpm
B. 60-100 bpm
C. 100-120 bpm
D. 120-160 bpm
Answer: B
Rationale: Normal sinus rhythm is defined as a rate between 60 and 100 beats per minute. Below 60
is bradycardia; above 100 is tachycardia.
Chapter 2 & 3: Electrophysiology & Waveforms
11. The T wave on an ECG represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. Atrial repolarization
Answer: C
Rationale: The T wave represents the repolarization (recovery) of the ventricles. Atrial repolarization
is usually hidden in the QRS complex.
12. A normal QRS complex duration is:
A. Less than 0.12 seconds (3 small squares)
B. 0.12 to 0.20 seconds
C. Greater than 0.20 seconds
D. 0.04 to 0.10 seconds
Answer: A
Interpretation, 8th Edition by Jane Huff | Original
Test Bank-S
1. Which structure is the primary pacemaker of the heart, initiating the electrical impulse that
produces the P wave?
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node
C. Bundle of His
D. Purkinje fibers
Answer: B
Rationale: The SA node, located in the upper right atrium, has the highest automaticity and normally
initiates the electrical impulse, resulting in atrial depolarization (the P wave). The AV node delays the
impulse, while the Bundle of His and Purkinje fibers conduct it to the ventricles.
2. The PR interval represents the time required for the electrical impulse to travel from the:
A. SA node to the atrial myocardium
B. AV node to the Purkinje fibers
C. Atria through the AV node to the ventricles
D. Ventricles to repolarize
Answer: C
Rationale: The PR interval measures the time from the beginning of atrial depolarization to the
beginning of ventricular depolarization. This includes the delay at the AV node, which allows the
ventricles time to fill.
3. Which heart layer is the thickest and responsible for the forceful contraction of the heart?
A. Epicardium
B. Endocardium
C. Myocardium
,D. Pericardium
Answer: C
Rationale: The myocardium is the middle, muscular layer of the heart wall. It contains the contractile
muscle fibers (cardiomyocytes) that generate the force necessary to pump blood.
4. Blood flow from the right ventricle travels through which valve to reach the lungs?
A. Mitral valve
B. Aortic valve
C. Pulmonic valve
D. Tricuspid valve
Answer: C
Rationale: The right ventricle pumps deoxygenated blood through the pulmonic (pulmonary) valve
into the pulmonary artery, which leads to the lungs for gas exchange.
5. Which coronary artery is most commonly occluded, often leading to significant anterior wall
myocardial infarction?
A. Right coronary artery (RCA)
B. Left anterior descending (LAD) artery
C. Circumflex artery
D. Posterior descending artery
Answer: B
Rationale: The LAD supplies the anterior wall of the left ventricle and the anterior portion of the
ventricular septum. Occlusion here is common and often referred to as the "widow-maker" due to
the large area of myocardium at risk.
6. Which surface of the heart is the apex located against?
A. The diaphragm
B. The sternum
C. The left lung
D. The vertebral column
,Answer: A
Rationale: The apex (the pointed inferior tip of the left ventricle) rests on the diaphragm. This is why
it is often palpated at the 5th intercostal space, midclavicular line.
7. During which phase of the cardiac cycle do the coronary arteries primarily receive blood flow?
A. Ventricular systole
B. Ventricular diastole
C. Atrial systole
D. Isovolumetric contraction
Answer: B
Rationale: During ventricular contraction (systole), the myocardium compresses the coronary
arteries, restricting flow. The coronary arteries fill primarily during ventricular relaxation (diastole)
when the myocardium is relaxed.
8. Which structure delays the electrical impulse to allow for ventricular filling?
A. SA node
B. AV node
C. Bundle branches
D. Purkinje network
Answer: B
Rationale: The AV node intentionally slows conduction (creating the PR segment). This delay ensures
the atria have time to contract and empty blood into the ventricles before the ventricles contract.
9. The systemic circuit begins in which chamber of the heart?
A. Right atrium
B. Right ventricle
C. Left atrium
D. Left ventricle
, Answer: D
Rationale: The left ventricle pumps oxygenated blood into the aorta to begin the high-pressure
systemic circuit, delivering blood to the body tissues.
10. What is the normal resting heart rate for a healthy adult?
A. 40-60 bpm
B. 60-100 bpm
C. 100-120 bpm
D. 120-160 bpm
Answer: B
Rationale: Normal sinus rhythm is defined as a rate between 60 and 100 beats per minute. Below 60
is bradycardia; above 100 is tachycardia.
Chapter 2 & 3: Electrophysiology & Waveforms
11. The T wave on an ECG represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. Atrial repolarization
Answer: C
Rationale: The T wave represents the repolarization (recovery) of the ventricles. Atrial repolarization
is usually hidden in the QRS complex.
12. A normal QRS complex duration is:
A. Less than 0.12 seconds (3 small squares)
B. 0.12 to 0.20 seconds
C. Greater than 0.20 seconds
D. 0.04 to 0.10 seconds
Answer: A
