HEART FAILURE QUESTIONS AND ANSWERS WITH
RATIONALES/GRADED A+/2026 UPDATE/100%
CORRECT
Section 1: Anatomy & Physiology of the Heart
1. The normal resting cardiac output in an average adult is approximately:
A) 5 L/min
B) 10 L/min
C) 2 L/min
D) 15 L/min
*Rationale: Cardiac output (CO) is the volume of blood pumped by the heart per
minute, normally about 5 L/min at rest (heart rate × stroke volume, ~70 bpm × 70
mL/beat = ~5 L/min).*
2. The Frank-Starling law states that:
A) The stroke volume of the heart increases in response to an increase in the
volume of blood filling the heart (end-diastolic volume)
B) The heart rate increases with increased preload
C) Contractility is independent of preload
D) Afterload is the primary determinant of stroke volume
Rationale: The Frank-Starling mechanism describes how increased venous return
(preload) stretches the myocardial fibers, increasing the force of contraction and
stroke volume, up to a physiologic limit.
3. Which of the following is the primary determinant of preload?
A) Venous return and end-diastolic volume
B) Systemic vascular resistance
C) Aortic impedance
D) Heart rate
,Rationale: Preload is the ventricular wall tension at end-diastole, primarily
determined by venous return and the resultant end-diastolic volume. It reflects the
degree of myocardial stretch before contraction.
4. Afterload is best defined as:
A) The volume of blood in the ventricle at end-diastole
B) The resistance the left ventricle must overcome to eject blood (systemic
vascular resistance)
C) The contractile state of the myocardium
D) The heart rate
Rationale: Afterload is the pressure (or resistance) that the left ventricle must
generate to eject blood into the aorta, primarily determined by systemic vascular
resistance (SVR) and aortic impedance.
5. The formula for cardiac output is:
A) Stroke volume × Heart rate
B) Blood pressure × Heart rate
C) Stroke volume / Heart rate
D) End-diastolic volume – End-systolic volume
Rationale: Cardiac output (CO) equals stroke volume (SV, the volume ejected per
beat) multiplied by heart rate (HR, beats per minute). SV is the difference between
end-diastolic and end-systolic volumes.
6. Ejection fraction (EF) is defined as:
A) Stroke volume / End-diastolic volume
B) End-systolic volume / End-diastolic volume
C) Stroke volume × Heart rate
D) Cardiac output / Body surface area
*Rationale: Ejection fraction is the fraction of end-diastolic volume ejected with
each beat. Normal EF is ≥55%. Reduced EF (≤40%) indicates systolic heart failure
(HFrEF).*
7. The majority of myocardial oxygen consumption is determined by:
A) Heart rate and contractility (wall stress)
,B) Stroke volume alone
C) Preload alone
D) Afterload alone
Rationale: Myocardial oxygen demand is primarily determined by heart rate,
myocardial contractility, and wall stress (which is influenced by preload and
afterload). Tachycardia and increased contractility increase oxygen demand.
8. The cardiac conduction system's primary pacemaker is the:
A) Atrioventricular (AV) node
B) Bundle of His
C) Sinoatrial (SA) node
D) Purkinje fibers
*Rationale: The SA node is the natural pacemaker of the heart, generating
impulses at 60-100 bpm. The AV node (40-60 bpm) and Purkinje fibers (20-40
bpm) serve as backup pacemakers.*
9. The force of myocardial contraction (inotropy) is increased by:
A) Beta-1 adrenergic stimulation (e.g., norepinephrine)
B) Vagal stimulation
C) Beta-blockers
D) Calcium channel blockers
*Rationale: Beta-1 adrenergic receptor stimulation increases intracellular cyclic
AMP, enhancing calcium influx into cardiac myocytes, thereby increasing
contractility (positive inotropy).*
10. The baroreceptor reflex responds to decreased blood pressure by:
A) Increasing sympathetic outflow (increased heart rate and contractility) and
decreasing parasympathetic tone
B) Decreasing sympathetic outflow
C) Increasing parasympathetic tone
D) Decreasing heart rate
Rationale: When blood pressure drops, baroreceptors in the carotid sinus and
aortic arch are less stimulated, leading to increased sympathetic activity
, (vasoconstriction, tachycardia, increased contractility) and reduced vagal tone to
restore blood pressure.
Section 2: Heart Failure – Definition, Classification & Pathophysiology (Questions
11–35)
11. Heart failure is best defined as:
A) A clinical syndrome characterized by structural or functional cardiac
abnormality resulting in inability to meet metabolic demands
B) A single disease with a single cause
C) Only left ventricular systolic dysfunction
D) A disease only of the elderly
Rationale: Heart failure is a complex clinical syndrome resulting from any
structural or functional impairment of ventricular filling or ejection. It is not a
single disease but a syndrome with multiple etiologies.
12. Heart failure with reduced ejection fraction (HFrEF) is defined as:
A) EF ≤ 40% with signs/symptoms of heart failure
B) EF ≥ 50% with signs/symptoms of heart failure
C) EF 41-49% with signs/symptoms of heart failure
D) EF > 60%
*Rationale: HFrEF (systolic HF) is defined by an EF ≤40%. HF with mid-range EF
(HFmrEF) is 41-49%, and HF with preserved EF (HFpEF) is ≥50%.*
13. Heart failure with preserved ejection fraction (HFpEF) is characterized by:
A) Normal or near-normal EF (≥50%) with impaired ventricular relaxation
(diastolic dysfunction)
B) Reduced EF with systolic dysfunction
C) Dilated cardiomyopathy
D) Valvular stenosis
RATIONALES/GRADED A+/2026 UPDATE/100%
CORRECT
Section 1: Anatomy & Physiology of the Heart
1. The normal resting cardiac output in an average adult is approximately:
A) 5 L/min
B) 10 L/min
C) 2 L/min
D) 15 L/min
*Rationale: Cardiac output (CO) is the volume of blood pumped by the heart per
minute, normally about 5 L/min at rest (heart rate × stroke volume, ~70 bpm × 70
mL/beat = ~5 L/min).*
2. The Frank-Starling law states that:
A) The stroke volume of the heart increases in response to an increase in the
volume of blood filling the heart (end-diastolic volume)
B) The heart rate increases with increased preload
C) Contractility is independent of preload
D) Afterload is the primary determinant of stroke volume
Rationale: The Frank-Starling mechanism describes how increased venous return
(preload) stretches the myocardial fibers, increasing the force of contraction and
stroke volume, up to a physiologic limit.
3. Which of the following is the primary determinant of preload?
A) Venous return and end-diastolic volume
B) Systemic vascular resistance
C) Aortic impedance
D) Heart rate
,Rationale: Preload is the ventricular wall tension at end-diastole, primarily
determined by venous return and the resultant end-diastolic volume. It reflects the
degree of myocardial stretch before contraction.
4. Afterload is best defined as:
A) The volume of blood in the ventricle at end-diastole
B) The resistance the left ventricle must overcome to eject blood (systemic
vascular resistance)
C) The contractile state of the myocardium
D) The heart rate
Rationale: Afterload is the pressure (or resistance) that the left ventricle must
generate to eject blood into the aorta, primarily determined by systemic vascular
resistance (SVR) and aortic impedance.
5. The formula for cardiac output is:
A) Stroke volume × Heart rate
B) Blood pressure × Heart rate
C) Stroke volume / Heart rate
D) End-diastolic volume – End-systolic volume
Rationale: Cardiac output (CO) equals stroke volume (SV, the volume ejected per
beat) multiplied by heart rate (HR, beats per minute). SV is the difference between
end-diastolic and end-systolic volumes.
6. Ejection fraction (EF) is defined as:
A) Stroke volume / End-diastolic volume
B) End-systolic volume / End-diastolic volume
C) Stroke volume × Heart rate
D) Cardiac output / Body surface area
*Rationale: Ejection fraction is the fraction of end-diastolic volume ejected with
each beat. Normal EF is ≥55%. Reduced EF (≤40%) indicates systolic heart failure
(HFrEF).*
7. The majority of myocardial oxygen consumption is determined by:
A) Heart rate and contractility (wall stress)
,B) Stroke volume alone
C) Preload alone
D) Afterload alone
Rationale: Myocardial oxygen demand is primarily determined by heart rate,
myocardial contractility, and wall stress (which is influenced by preload and
afterload). Tachycardia and increased contractility increase oxygen demand.
8. The cardiac conduction system's primary pacemaker is the:
A) Atrioventricular (AV) node
B) Bundle of His
C) Sinoatrial (SA) node
D) Purkinje fibers
*Rationale: The SA node is the natural pacemaker of the heart, generating
impulses at 60-100 bpm. The AV node (40-60 bpm) and Purkinje fibers (20-40
bpm) serve as backup pacemakers.*
9. The force of myocardial contraction (inotropy) is increased by:
A) Beta-1 adrenergic stimulation (e.g., norepinephrine)
B) Vagal stimulation
C) Beta-blockers
D) Calcium channel blockers
*Rationale: Beta-1 adrenergic receptor stimulation increases intracellular cyclic
AMP, enhancing calcium influx into cardiac myocytes, thereby increasing
contractility (positive inotropy).*
10. The baroreceptor reflex responds to decreased blood pressure by:
A) Increasing sympathetic outflow (increased heart rate and contractility) and
decreasing parasympathetic tone
B) Decreasing sympathetic outflow
C) Increasing parasympathetic tone
D) Decreasing heart rate
Rationale: When blood pressure drops, baroreceptors in the carotid sinus and
aortic arch are less stimulated, leading to increased sympathetic activity
, (vasoconstriction, tachycardia, increased contractility) and reduced vagal tone to
restore blood pressure.
Section 2: Heart Failure – Definition, Classification & Pathophysiology (Questions
11–35)
11. Heart failure is best defined as:
A) A clinical syndrome characterized by structural or functional cardiac
abnormality resulting in inability to meet metabolic demands
B) A single disease with a single cause
C) Only left ventricular systolic dysfunction
D) A disease only of the elderly
Rationale: Heart failure is a complex clinical syndrome resulting from any
structural or functional impairment of ventricular filling or ejection. It is not a
single disease but a syndrome with multiple etiologies.
12. Heart failure with reduced ejection fraction (HFrEF) is defined as:
A) EF ≤ 40% with signs/symptoms of heart failure
B) EF ≥ 50% with signs/symptoms of heart failure
C) EF 41-49% with signs/symptoms of heart failure
D) EF > 60%
*Rationale: HFrEF (systolic HF) is defined by an EF ≤40%. HF with mid-range EF
(HFmrEF) is 41-49%, and HF with preserved EF (HFpEF) is ≥50%.*
13. Heart failure with preserved ejection fraction (HFpEF) is characterized by:
A) Normal or near-normal EF (≥50%) with impaired ventricular relaxation
(diastolic dysfunction)
B) Reduced EF with systolic dysfunction
C) Dilated cardiomyopathy
D) Valvular stenosis
