DISORDERS OF CARDIAC CONDUCTION AND RHYTHM:
ECG AND PATHOPHYSIOLOGY |COMPLETE STUDY GUIDE
WITH 100% ACCURATE QUESTIONS &ANSWERS.
EXCELLENCE GUARANTEED.
What is the primary function of the cardiac conduction system? Answer: To generate and
conduct electrical impulses that maintain the heart's rhythm.
What are the five phases of cardiac action potential? Answer: Phase 0: Rapid depolarization,
Phase 1: Initial repolarization, Phase 2: Plateau phase, Phase 3: Rapid repolarization, Phase 4:
Resting potential.
What is an ECG and what does it record? Answer: An electrocardiogram (ECG) records the
electrical signals of the heart's conduction system.
What are the effects of atrial flutter on heart rhythm? Answer: Atrial flutter can lead to rapid
heart rates and may cause inefficient blood flow.
What is atrial fibrillation (AF)? Answer: Atrial fibrillation is a type of arrhythmia characterized
by rapid and irregular beating of the atria.
What are the characteristics of first-degree heart block? Answer: First-degree heart block is
characterized by a prolonged PR interval on the ECG but all impulses are conducted to the
ventricles.
What distinguishes second-degree heart block from first-degree heart block? Answer: In second-
degree heart block, some impulses are not conducted to the ventricles, resulting in dropped beats.
What is third-degree heart block? Answer: Third-degree heart block is a complete block where
no impulses from the atria are conducted to the ventricles.
1
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,What is ventricular tachycardia? Answer: Ventricular tachycardia is a fast heart rhythm
originating from the ventricles, which can be life-threatening.
What is ventricular fibrillation? Answer: Ventricular fibrillation is a chaotic heart rhythm that
results in ineffective quivering of the ventricles and can lead to cardiac arrest.
What is the sinoatrial (SA) node? Answer: The SA node is the heart's natural pacemaker,
generating impulses at a rate of 60 to 100 beats per minute.
What role does the atrioventricular (AV) node play in the conduction system? Answer: The AV
node conducts impulses from the atria to the ventricles and provides a delay to ensure the atria
empty before ventricular contraction.
What are the three internodal pathways between the SA node and the AV node? Answer: The
three internodal pathways are the anterior (Bachmann), middle (Wenckebach), and posterior
(Thorel) tracts.
What is the bundle of His? Answer: The bundle of His is a collection of heart muscle cells that
transmits impulses from the AV node to the ventricles.
What is the function of Purkinje fibers? Answer: Purkinje fibers rapidly conduct impulses
throughout the ventricles to ensure coordinated contraction.
What happens if the SA node fails to discharge? Answer: If the SA node fails, the AV node can
assume the pacemaker function, and if it fails, the Purkinje system can take over.
What is the intrinsic firing rate of the AV node? Answer: The intrinsic firing rate of the AV node
is 40 to 60 beats per minute.
What is the intrinsic firing rate of the Purkinje fibers? Answer: The intrinsic firing rate of the
Purkinje fibers is 15 to 40 beats per minute.
What is self-excitation in the context of cardiac cells? Answer: Self-excitation is the ability of
specialized cardiac cells to initiate and conduct electrical impulses.
2
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, What is the significance of the AV node's location? Answer: The AV node's location allows it to
coordinate conduction between the atria and ventricles, preventing independent contractions.
What is the purpose of the delay in conduction through the AV node? Answer: The delay allows
the atria to complete their contraction and empty blood into the ventricles before ventricular
contraction begins.
What can cause ischemic damage to the bundle of His? Answer: Extensive damage to the
coronary arteries can lead to ischemic damage affecting the bundle of His.
How does the Purkinje system ensure efficient blood ejection from the heart? Answer: The
Purkinje system conducts impulses rapidly, allowing for swift and coordinated contraction of the
ventricles.
What is the relationship between the SA node and the AV node in a healthy heart? Answer: The
SA node discharges impulses faster than the AV node, ensuring that the atria and ventricles beat
in sync.
What is the anatomical location of the SA node? Answer: The SA node is located in the posterior
wall of the right atrium, just below the opening of the superior vena cava.
What is the role of the coronary arteries in relation to the conduction system? Answer: The
coronary arteries supply blood to the conduction system, helping to prevent ischemic damage.
What are the five phases of cardiac action potentials? Answer: Phase 0: rapid upstroke; Phase 1:
early repolarization; Phase 2: plateau; Phase 3: final repolarization; Phase 4: diastolic
repolarization.
What does an action potential represent in cardiac cells? Answer: The sequential change in
electrical potential across a cell membrane when excitation occurs.
Which ions are the major charge carriers in cardiac muscle cells? Answer: Sodium (Na+),
potassium (K+), and calcium (Ca++).
3
APPHIA - Crafted with Care and Precision for Academic Excellence.
ECG AND PATHOPHYSIOLOGY |COMPLETE STUDY GUIDE
WITH 100% ACCURATE QUESTIONS &ANSWERS.
EXCELLENCE GUARANTEED.
What is the primary function of the cardiac conduction system? Answer: To generate and
conduct electrical impulses that maintain the heart's rhythm.
What are the five phases of cardiac action potential? Answer: Phase 0: Rapid depolarization,
Phase 1: Initial repolarization, Phase 2: Plateau phase, Phase 3: Rapid repolarization, Phase 4:
Resting potential.
What is an ECG and what does it record? Answer: An electrocardiogram (ECG) records the
electrical signals of the heart's conduction system.
What are the effects of atrial flutter on heart rhythm? Answer: Atrial flutter can lead to rapid
heart rates and may cause inefficient blood flow.
What is atrial fibrillation (AF)? Answer: Atrial fibrillation is a type of arrhythmia characterized
by rapid and irregular beating of the atria.
What are the characteristics of first-degree heart block? Answer: First-degree heart block is
characterized by a prolonged PR interval on the ECG but all impulses are conducted to the
ventricles.
What distinguishes second-degree heart block from first-degree heart block? Answer: In second-
degree heart block, some impulses are not conducted to the ventricles, resulting in dropped beats.
What is third-degree heart block? Answer: Third-degree heart block is a complete block where
no impulses from the atria are conducted to the ventricles.
1
APPHIA - Crafted with Care and Precision for Academic Excellence.
,What is ventricular tachycardia? Answer: Ventricular tachycardia is a fast heart rhythm
originating from the ventricles, which can be life-threatening.
What is ventricular fibrillation? Answer: Ventricular fibrillation is a chaotic heart rhythm that
results in ineffective quivering of the ventricles and can lead to cardiac arrest.
What is the sinoatrial (SA) node? Answer: The SA node is the heart's natural pacemaker,
generating impulses at a rate of 60 to 100 beats per minute.
What role does the atrioventricular (AV) node play in the conduction system? Answer: The AV
node conducts impulses from the atria to the ventricles and provides a delay to ensure the atria
empty before ventricular contraction.
What are the three internodal pathways between the SA node and the AV node? Answer: The
three internodal pathways are the anterior (Bachmann), middle (Wenckebach), and posterior
(Thorel) tracts.
What is the bundle of His? Answer: The bundle of His is a collection of heart muscle cells that
transmits impulses from the AV node to the ventricles.
What is the function of Purkinje fibers? Answer: Purkinje fibers rapidly conduct impulses
throughout the ventricles to ensure coordinated contraction.
What happens if the SA node fails to discharge? Answer: If the SA node fails, the AV node can
assume the pacemaker function, and if it fails, the Purkinje system can take over.
What is the intrinsic firing rate of the AV node? Answer: The intrinsic firing rate of the AV node
is 40 to 60 beats per minute.
What is the intrinsic firing rate of the Purkinje fibers? Answer: The intrinsic firing rate of the
Purkinje fibers is 15 to 40 beats per minute.
What is self-excitation in the context of cardiac cells? Answer: Self-excitation is the ability of
specialized cardiac cells to initiate and conduct electrical impulses.
2
APPHIA - Crafted with Care and Precision for Academic Excellence.
, What is the significance of the AV node's location? Answer: The AV node's location allows it to
coordinate conduction between the atria and ventricles, preventing independent contractions.
What is the purpose of the delay in conduction through the AV node? Answer: The delay allows
the atria to complete their contraction and empty blood into the ventricles before ventricular
contraction begins.
What can cause ischemic damage to the bundle of His? Answer: Extensive damage to the
coronary arteries can lead to ischemic damage affecting the bundle of His.
How does the Purkinje system ensure efficient blood ejection from the heart? Answer: The
Purkinje system conducts impulses rapidly, allowing for swift and coordinated contraction of the
ventricles.
What is the relationship between the SA node and the AV node in a healthy heart? Answer: The
SA node discharges impulses faster than the AV node, ensuring that the atria and ventricles beat
in sync.
What is the anatomical location of the SA node? Answer: The SA node is located in the posterior
wall of the right atrium, just below the opening of the superior vena cava.
What is the role of the coronary arteries in relation to the conduction system? Answer: The
coronary arteries supply blood to the conduction system, helping to prevent ischemic damage.
What are the five phases of cardiac action potentials? Answer: Phase 0: rapid upstroke; Phase 1:
early repolarization; Phase 2: plateau; Phase 3: final repolarization; Phase 4: diastolic
repolarization.
What does an action potential represent in cardiac cells? Answer: The sequential change in
electrical potential across a cell membrane when excitation occurs.
Which ions are the major charge carriers in cardiac muscle cells? Answer: Sodium (Na+),
potassium (K+), and calcium (Ca++).
3
APPHIA - Crafted with Care and Precision for Academic Excellence.
