,TABLE OF CONTENT
Chapter 1: Normal Cardiac Structure and Function
Chapter 2: The Cardiac Cycle — Mechanisms of Heart Sounds and Murmurs
Chapter 3: Cardiac Imaging and Hemodynamic Assessment
Chapter 4: The Electrocardiogram
Chapter 5: Atherosclerosis
Chapter 6: Ischemic Heart Disease
Chapter 7: Acute Coronary Syndromes
Chapter 8: Valvular Heart Disease
Chapter 9: Heart Failure
Chapter 10: The Cardiomyopathies
Chapter 11: Mechanisms of Cardiac Arrhythmias
Chapter 12: Clinical Aspects of Cardiac Arrhythmias
Chapter 13: Hypertension
Chapter 14: Diseases of the Pericardium
Chapter 15: Diseases of the Peripheral Vasculature
Chapter 16: Congenital Heart Disease
Chapter 17: Cardiovascular Drugs
,Chapter 1: Normal Cardiac Structure and Function
Question 1
Which structure is primarily responsible for initiating the cardiac action potential?
A. Atrioventricular (AV) node
B. Purkinje fibers
C. Sinoatrial (SA) node
D. Bundle of His
Answer: C
Rationale: The SA node is the heart’s primary pacemaker, initiating
spontaneous depolarization that propagates through the atria and AV node. The
AV node and Purkinje fibers conduct the impulse, but they have slower intrinsic
firing rates.
Keywords: SA node, pacemaker, cardiac conduction, depolarization
Question 2
Which of the following best represents the relationship between preload and
stroke volume?
A. Stroke volume decreases as preload increases
B. Stroke volume is independent of preload
C. Stroke volume increases as preload increases
D. Preload only affects heart rate, not stroke volume
,Answer: C
Rationale: Preload refers to ventricular end-diastolic volume. According to the
Frank-Starling mechanism, increasing preload stretches myocardial fibers,
enhancing contractile force and stroke volume up to a physiological limit.
Keywords: preload, Frank-Starling law, stroke volume, ventricular filling
Question 3
Which layer of the heart is primarily responsible for contractile function?
A. Epicardium
B. Myocardium
C. Endocardium
D. Pericardium
Answer: B
Rationale: The myocardium is composed of cardiac muscle cells (myocytes)
responsible for force generation and contraction. The epicardium and
endocardium are protective and structural layers, while the pericardium encases
the heart.
Keywords: myocardium, contraction, cardiac muscle, heart layers
Question 4
Which valve prevents backflow of blood from the left ventricle into the left
atrium during systole?
A. Tricuspid valve
,B. Mitral (bicuspid) valve
C. Pulmonary valve
D. Aortic valve
Answer: B
Rationale: The mitral valve (bicuspid) ensures unidirectional flow from the left
atrium to the left ventricle during diastole and prevents regurgitation during
systole.
Keywords: mitral valve, systole, valve function, regurgitation
Question 5
Which coronary artery primarily supplies the interventricular septum?
A. Right coronary artery (RCA)
B. Left anterior descending artery (LAD)
C. Circumflex artery
D. Posterior descending artery (PDA)
Answer: B
Rationale: The LAD supplies the anterior interventricular septum, anterior wall,
and apex. The RCA and PDA supply the posterior septum and right heart
structures.
Keywords: coronary circulation, LAD, interventricular septum, myocardial
perfusion
Question 6
, During isovolumetric contraction, which statement is true regarding ventricular
pressure and volume?
A. Volume increases, pressure decreases
B. Pressure increases, volume remains constant
C. Volume decreases, pressure remains constant
D. Both pressure and volume decrease
Answer: B
Rationale: Isovolumetric contraction occurs after AV valve closure and before
semilunar valve opening; the ventricles generate pressure without a change in
volume.
Keywords: isovolumetric contraction, ventricular pressure, cardiac cycle, systole
Question 7
Which ionic movement predominantly underlies phase 0 of the cardiac action
potential in ventricular myocytes?
A. Calcium influx
B. Sodium influx
C. Potassium efflux
D. Chloride influx
Answer: B
Rationale: Phase 0 represents rapid depolarization mediated by the fast sodium
channels opening, causing a rapid influx of Na⁺ into the cell. Calcium influx
dominates later phases.
Keywords: cardiac action potential, phase 0, sodium influx, ventricular myocytes
Chapter 1: Normal Cardiac Structure and Function
Chapter 2: The Cardiac Cycle — Mechanisms of Heart Sounds and Murmurs
Chapter 3: Cardiac Imaging and Hemodynamic Assessment
Chapter 4: The Electrocardiogram
Chapter 5: Atherosclerosis
Chapter 6: Ischemic Heart Disease
Chapter 7: Acute Coronary Syndromes
Chapter 8: Valvular Heart Disease
Chapter 9: Heart Failure
Chapter 10: The Cardiomyopathies
Chapter 11: Mechanisms of Cardiac Arrhythmias
Chapter 12: Clinical Aspects of Cardiac Arrhythmias
Chapter 13: Hypertension
Chapter 14: Diseases of the Pericardium
Chapter 15: Diseases of the Peripheral Vasculature
Chapter 16: Congenital Heart Disease
Chapter 17: Cardiovascular Drugs
,Chapter 1: Normal Cardiac Structure and Function
Question 1
Which structure is primarily responsible for initiating the cardiac action potential?
A. Atrioventricular (AV) node
B. Purkinje fibers
C. Sinoatrial (SA) node
D. Bundle of His
Answer: C
Rationale: The SA node is the heart’s primary pacemaker, initiating
spontaneous depolarization that propagates through the atria and AV node. The
AV node and Purkinje fibers conduct the impulse, but they have slower intrinsic
firing rates.
Keywords: SA node, pacemaker, cardiac conduction, depolarization
Question 2
Which of the following best represents the relationship between preload and
stroke volume?
A. Stroke volume decreases as preload increases
B. Stroke volume is independent of preload
C. Stroke volume increases as preload increases
D. Preload only affects heart rate, not stroke volume
,Answer: C
Rationale: Preload refers to ventricular end-diastolic volume. According to the
Frank-Starling mechanism, increasing preload stretches myocardial fibers,
enhancing contractile force and stroke volume up to a physiological limit.
Keywords: preload, Frank-Starling law, stroke volume, ventricular filling
Question 3
Which layer of the heart is primarily responsible for contractile function?
A. Epicardium
B. Myocardium
C. Endocardium
D. Pericardium
Answer: B
Rationale: The myocardium is composed of cardiac muscle cells (myocytes)
responsible for force generation and contraction. The epicardium and
endocardium are protective and structural layers, while the pericardium encases
the heart.
Keywords: myocardium, contraction, cardiac muscle, heart layers
Question 4
Which valve prevents backflow of blood from the left ventricle into the left
atrium during systole?
A. Tricuspid valve
,B. Mitral (bicuspid) valve
C. Pulmonary valve
D. Aortic valve
Answer: B
Rationale: The mitral valve (bicuspid) ensures unidirectional flow from the left
atrium to the left ventricle during diastole and prevents regurgitation during
systole.
Keywords: mitral valve, systole, valve function, regurgitation
Question 5
Which coronary artery primarily supplies the interventricular septum?
A. Right coronary artery (RCA)
B. Left anterior descending artery (LAD)
C. Circumflex artery
D. Posterior descending artery (PDA)
Answer: B
Rationale: The LAD supplies the anterior interventricular septum, anterior wall,
and apex. The RCA and PDA supply the posterior septum and right heart
structures.
Keywords: coronary circulation, LAD, interventricular septum, myocardial
perfusion
Question 6
, During isovolumetric contraction, which statement is true regarding ventricular
pressure and volume?
A. Volume increases, pressure decreases
B. Pressure increases, volume remains constant
C. Volume decreases, pressure remains constant
D. Both pressure and volume decrease
Answer: B
Rationale: Isovolumetric contraction occurs after AV valve closure and before
semilunar valve opening; the ventricles generate pressure without a change in
volume.
Keywords: isovolumetric contraction, ventricular pressure, cardiac cycle, systole
Question 7
Which ionic movement predominantly underlies phase 0 of the cardiac action
potential in ventricular myocytes?
A. Calcium influx
B. Sodium influx
C. Potassium efflux
D. Chloride influx
Answer: B
Rationale: Phase 0 represents rapid depolarization mediated by the fast sodium
channels opening, causing a rapid influx of Na⁺ into the cell. Calcium influx
dominates later phases.
Keywords: cardiac action potential, phase 0, sodium influx, ventricular myocytes
