PARA320 Cardiology for Paramedics Exam Prep – Real Practice Questions,
Answers & Detailed Rationales (Updated 2026) | Cardiac Anatomy &
Physiology, ECG Interpretation & Dysrhythmias, ACLS Algorithms, Cardiac
Emergencies & Pharmacology, STEMI Recognition, Defibrillation & Cardioversion,
Heart Failure & Shock, Hemodynamic Monitoring, EMS Cardiac Care & Clinical
Scenarios
Question 1: Which cardiac chamber is responsible for pumping oxygenated blood
into the systemic circulation via the aorta?
A. Right atrium
B. Right ventricle
C. Left atrium
D. Left ventricle
CORRECT ANSWER: D. Left ventricle
Rationale: The left ventricle has the thickest myocardial wall of all cardiac chambers
because it must generate sufficient pressure to propel oxygenated blood through the
aortic valve and into the systemic arterial circulation. The right ventricle pumps
deoxygenated blood to the lungs via the pulmonary artery, while the atria primarily
function as receiving chambers.
Question 2: During pre-hospital assessment of a patient with suspected acute
coronary syndrome, which ECG finding is most indicative of an acute ST-elevation
myocardial infarction (STEMI)?
A. T-wave inversion in lead V3
B. ST-segment elevation of 2 mm in two contiguous leads
C. Prolonged PR interval of 240 ms
D. QRS duration of 110 ms
CORRECT ANSWER: B. ST-segment elevation of 2 mm in two contiguous leads
Rationale: STEMI is diagnosed when there is ST-segment elevation of ≥1 mm in two or
more contiguous limb leads or ≥2 mm in two or more contiguous precordial leads,
indicating acute transmural myocardial injury. This finding requires immediate
reperfusion therapy. T-wave inversion may indicate ischemia but is not diagnostic of
STEMI; prolonged PR interval suggests first-degree AV block; widened QRS may indicate
bundle branch block.
Question 3: A paramedic administers sublingual nitroglycerin to a patient with
chest pain. Which physiological effect is the primary therapeutic goal of this
intervention?
A. Increased myocardial contractility
B. Coronary artery vasodilation and reduced preload
C. Slowed atrioventricular nodal conduction
D. Enhanced platelet aggregation
CORRECT ANSWER: B. Coronary artery vasodilation and reduced preload
,Rationale: Nitroglycerin is a venous and arterial vasodilator that primarily reduces
preload by pooling blood in the venous system, thereby decreasing myocardial oxygen
demand. It also dilates coronary arteries to improve blood flow to ischemic
myocardium. It does not increase contractility (which would increase oxygen demand),
slow AV conduction (a property of beta-blockers or calcium channel blockers), or
enhance platelet aggregation (aspirin inhibits aggregation).
Question 4: Which rhythm is characterized by the absence of P waves, an
irregularly irregular ventricular response, and a QRS complex typically less than
120 ms?
A. Atrial flutter
B. Ventricular tachycardia
C. Atrial fibrillation
D. Sinus arrhythmia
CORRECT ANSWER: C. Atrial fibrillation
Rationale: Atrial fibrillation is identified on ECG by the absence of distinct P waves
(replaced by fibrillatory waves), an irregularly irregular R-R interval, and usually narrow
QRS complexes unless bundle branch block is present. Atrial flutter shows sawtooth
flutter waves; ventricular tachycardia has wide QRS complexes and AV dissociation;
sinus arrhythmia has normal P waves with physiologic variation in R-R interval related to
respiration.
Question 5: In the context of cardiac physiology, what does the term "preload" refer
to?
A. The resistance the left ventricle must overcome to eject blood
B. The volume of blood in the ventricle at the end of diastole
C. The contractile force generated by the myocardium
D. The heart rate multiplied by stroke volume
CORRECT ANSWER: B. The volume of blood in the ventricle at the end of diastole
Rationale: Preload is defined as the initial stretching of the cardiac myocytes prior to
contraction, clinically approximated by the end-diastolic volume. According to the
Frank-Starling mechanism, increased preload enhances stroke volume up to a
physiological limit. Afterload refers to ventricular ejection resistance; contractility is the
intrinsic strength of myocardial contraction; cardiac output equals heart rate times
stroke volume.
Question 6: A patient presents with sudden onset of severe, tearing chest pain
radiating to the back, asymmetric blood pressures in the arms, and a diastolic
murmur. Which life-threatening condition should the paramedic prioritize?
A. Acute pericarditis
B. Pulmonary embolism
,C. Aortic dissection
D. Unstable angina
CORRECT ANSWER: C. Aortic dissection
Rationale: Aortic dissection classically presents with abrupt, severe "tearing" or
"ripping" chest or back pain, pulse or blood pressure deficits between extremities due
to involvement of branch vessels, and possibly a new aortic regurgitation murmur if the
dissection involves the aortic valve. This is a surgical emergency. Pericarditis causes
pleuritic pain relieved by sitting forward; pulmonary embolism typically presents with
dyspnea and pleuritic pain; unstable angina causes pressure-like chest discomfort
without the tearing quality or pulse deficits.
Question 7: Which medication is contraindicated in a patient with suspected right
ventricular infarction?
A. Aspirin
B. Nitroglycerin
C. Morphine sulfate
D. Oxygen
CORRECT ANSWER: B. Nitroglycerin
Rationale: Right ventricular infarction often occurs with inferior wall MI and depends on
adequate preload to maintain cardiac output. Nitroglycerin reduces preload through
venodilation, which can precipitate profound hypotension in these patients. Aspirin is
indicated for all suspected ACS; morphine may be used cautiously for pain; oxygen is
administered if hypoxemic. Fluid resuscitation, not vasodilators, is often required for RV
infarction.
Question 8: What is the primary electrical event represented by the QRS complex
on a standard 12-lead ECG?
A. Atrial depolarization
B. Atrial repolarization
C. Ventricular depolarization
D. Ventricular repolarization
CORRECT ANSWER: C. Ventricular depolarization
Rationale: The QRS complex corresponds to the rapid depolarization of the right and left
ventricles, which triggers ventricular contraction. Atrial depolarization is represented by
the P wave; atrial repolarization is typically hidden within the QRS; ventricular
repolarization is represented by the T wave. Understanding ECG waveforms is essential
for paramedics to identify arrhythmias and ischemic changes.
Question 9: During cardiac arrest, a paramedic identifies a rhythm of coarse
ventricular fibrillation. What is the immediate next intervention according to
current ACLS guidelines?
, A. Administer epinephrine 1 mg IV
B. Perform immediate defibrillation at 200 J biphasic
C. Begin high-quality CPR for 2 minutes
D. Establish advanced airway management
CORRECT ANSWER: B. Perform immediate defibrillation at 200 J biphasic
Rationale: For witnessed ventricular fibrillation or pulseless ventricular tachycardia,
immediate defibrillation is the priority intervention to restore an organized rhythm.
Current guidelines emphasize minimizing pauses in CPR, but when VF/pVT is identified
on the monitor, defibrillation should occur as soon as the defibrillator is charged.
Epinephrine is administered after the first shock if ROSC is not achieved; CPR is
performed before rhythm checks; airway management is important but secondary to
defibrillation in shockable rhythms.
Question 10: Which cardiac valve prevents backflow of blood from the left ventricle
into the left atrium during systole?
A. Tricuspid valve
B. Pulmonary valve
C. Mitral valve
D. Aortic valve
CORRECT ANSWER: C. Mitral valve
Rationale: The mitral (bicuspid) valve is located between the left atrium and left
ventricle and closes during ventricular systole to prevent regurgitation of blood into the
atrium. The tricuspid valve serves the same function on the right side; the pulmonary
and aortic valves are semilunar valves that prevent backflow from the pulmonary artery
and aorta into their respective ventricles during diastole.
Question 11: A paramedic is assessing a patient with heart failure. Which clinical
sign is most specific for acute decompensated heart failure with pulmonary
edema?
A. Bilateral ankle edema
B. Jugular venous distension
C. Pink, frothy sputum
D. Hepatojugular reflux
CORRECT ANSWER: C. Pink, frothy sputum
Rationale: Pink, frothy sputum results from alveolar flooding with blood-tinged fluid due
to severe pulmonary edema, a hallmark of acute decompensated heart failure. While
ankle edema, JVD, and hepatojugular reflux indicate volume overload and right heart
strain, they are less specific for acute pulmonary edema. Pink frothy sputum signifies
imminent respiratory compromise requiring urgent intervention.
Answers & Detailed Rationales (Updated 2026) | Cardiac Anatomy &
Physiology, ECG Interpretation & Dysrhythmias, ACLS Algorithms, Cardiac
Emergencies & Pharmacology, STEMI Recognition, Defibrillation & Cardioversion,
Heart Failure & Shock, Hemodynamic Monitoring, EMS Cardiac Care & Clinical
Scenarios
Question 1: Which cardiac chamber is responsible for pumping oxygenated blood
into the systemic circulation via the aorta?
A. Right atrium
B. Right ventricle
C. Left atrium
D. Left ventricle
CORRECT ANSWER: D. Left ventricle
Rationale: The left ventricle has the thickest myocardial wall of all cardiac chambers
because it must generate sufficient pressure to propel oxygenated blood through the
aortic valve and into the systemic arterial circulation. The right ventricle pumps
deoxygenated blood to the lungs via the pulmonary artery, while the atria primarily
function as receiving chambers.
Question 2: During pre-hospital assessment of a patient with suspected acute
coronary syndrome, which ECG finding is most indicative of an acute ST-elevation
myocardial infarction (STEMI)?
A. T-wave inversion in lead V3
B. ST-segment elevation of 2 mm in two contiguous leads
C. Prolonged PR interval of 240 ms
D. QRS duration of 110 ms
CORRECT ANSWER: B. ST-segment elevation of 2 mm in two contiguous leads
Rationale: STEMI is diagnosed when there is ST-segment elevation of ≥1 mm in two or
more contiguous limb leads or ≥2 mm in two or more contiguous precordial leads,
indicating acute transmural myocardial injury. This finding requires immediate
reperfusion therapy. T-wave inversion may indicate ischemia but is not diagnostic of
STEMI; prolonged PR interval suggests first-degree AV block; widened QRS may indicate
bundle branch block.
Question 3: A paramedic administers sublingual nitroglycerin to a patient with
chest pain. Which physiological effect is the primary therapeutic goal of this
intervention?
A. Increased myocardial contractility
B. Coronary artery vasodilation and reduced preload
C. Slowed atrioventricular nodal conduction
D. Enhanced platelet aggregation
CORRECT ANSWER: B. Coronary artery vasodilation and reduced preload
,Rationale: Nitroglycerin is a venous and arterial vasodilator that primarily reduces
preload by pooling blood in the venous system, thereby decreasing myocardial oxygen
demand. It also dilates coronary arteries to improve blood flow to ischemic
myocardium. It does not increase contractility (which would increase oxygen demand),
slow AV conduction (a property of beta-blockers or calcium channel blockers), or
enhance platelet aggregation (aspirin inhibits aggregation).
Question 4: Which rhythm is characterized by the absence of P waves, an
irregularly irregular ventricular response, and a QRS complex typically less than
120 ms?
A. Atrial flutter
B. Ventricular tachycardia
C. Atrial fibrillation
D. Sinus arrhythmia
CORRECT ANSWER: C. Atrial fibrillation
Rationale: Atrial fibrillation is identified on ECG by the absence of distinct P waves
(replaced by fibrillatory waves), an irregularly irregular R-R interval, and usually narrow
QRS complexes unless bundle branch block is present. Atrial flutter shows sawtooth
flutter waves; ventricular tachycardia has wide QRS complexes and AV dissociation;
sinus arrhythmia has normal P waves with physiologic variation in R-R interval related to
respiration.
Question 5: In the context of cardiac physiology, what does the term "preload" refer
to?
A. The resistance the left ventricle must overcome to eject blood
B. The volume of blood in the ventricle at the end of diastole
C. The contractile force generated by the myocardium
D. The heart rate multiplied by stroke volume
CORRECT ANSWER: B. The volume of blood in the ventricle at the end of diastole
Rationale: Preload is defined as the initial stretching of the cardiac myocytes prior to
contraction, clinically approximated by the end-diastolic volume. According to the
Frank-Starling mechanism, increased preload enhances stroke volume up to a
physiological limit. Afterload refers to ventricular ejection resistance; contractility is the
intrinsic strength of myocardial contraction; cardiac output equals heart rate times
stroke volume.
Question 6: A patient presents with sudden onset of severe, tearing chest pain
radiating to the back, asymmetric blood pressures in the arms, and a diastolic
murmur. Which life-threatening condition should the paramedic prioritize?
A. Acute pericarditis
B. Pulmonary embolism
,C. Aortic dissection
D. Unstable angina
CORRECT ANSWER: C. Aortic dissection
Rationale: Aortic dissection classically presents with abrupt, severe "tearing" or
"ripping" chest or back pain, pulse or blood pressure deficits between extremities due
to involvement of branch vessels, and possibly a new aortic regurgitation murmur if the
dissection involves the aortic valve. This is a surgical emergency. Pericarditis causes
pleuritic pain relieved by sitting forward; pulmonary embolism typically presents with
dyspnea and pleuritic pain; unstable angina causes pressure-like chest discomfort
without the tearing quality or pulse deficits.
Question 7: Which medication is contraindicated in a patient with suspected right
ventricular infarction?
A. Aspirin
B. Nitroglycerin
C. Morphine sulfate
D. Oxygen
CORRECT ANSWER: B. Nitroglycerin
Rationale: Right ventricular infarction often occurs with inferior wall MI and depends on
adequate preload to maintain cardiac output. Nitroglycerin reduces preload through
venodilation, which can precipitate profound hypotension in these patients. Aspirin is
indicated for all suspected ACS; morphine may be used cautiously for pain; oxygen is
administered if hypoxemic. Fluid resuscitation, not vasodilators, is often required for RV
infarction.
Question 8: What is the primary electrical event represented by the QRS complex
on a standard 12-lead ECG?
A. Atrial depolarization
B. Atrial repolarization
C. Ventricular depolarization
D. Ventricular repolarization
CORRECT ANSWER: C. Ventricular depolarization
Rationale: The QRS complex corresponds to the rapid depolarization of the right and left
ventricles, which triggers ventricular contraction. Atrial depolarization is represented by
the P wave; atrial repolarization is typically hidden within the QRS; ventricular
repolarization is represented by the T wave. Understanding ECG waveforms is essential
for paramedics to identify arrhythmias and ischemic changes.
Question 9: During cardiac arrest, a paramedic identifies a rhythm of coarse
ventricular fibrillation. What is the immediate next intervention according to
current ACLS guidelines?
, A. Administer epinephrine 1 mg IV
B. Perform immediate defibrillation at 200 J biphasic
C. Begin high-quality CPR for 2 minutes
D. Establish advanced airway management
CORRECT ANSWER: B. Perform immediate defibrillation at 200 J biphasic
Rationale: For witnessed ventricular fibrillation or pulseless ventricular tachycardia,
immediate defibrillation is the priority intervention to restore an organized rhythm.
Current guidelines emphasize minimizing pauses in CPR, but when VF/pVT is identified
on the monitor, defibrillation should occur as soon as the defibrillator is charged.
Epinephrine is administered after the first shock if ROSC is not achieved; CPR is
performed before rhythm checks; airway management is important but secondary to
defibrillation in shockable rhythms.
Question 10: Which cardiac valve prevents backflow of blood from the left ventricle
into the left atrium during systole?
A. Tricuspid valve
B. Pulmonary valve
C. Mitral valve
D. Aortic valve
CORRECT ANSWER: C. Mitral valve
Rationale: The mitral (bicuspid) valve is located between the left atrium and left
ventricle and closes during ventricular systole to prevent regurgitation of blood into the
atrium. The tricuspid valve serves the same function on the right side; the pulmonary
and aortic valves are semilunar valves that prevent backflow from the pulmonary artery
and aorta into their respective ventricles during diastole.
Question 11: A paramedic is assessing a patient with heart failure. Which clinical
sign is most specific for acute decompensated heart failure with pulmonary
edema?
A. Bilateral ankle edema
B. Jugular venous distension
C. Pink, frothy sputum
D. Hepatojugular reflux
CORRECT ANSWER: C. Pink, frothy sputum
Rationale: Pink, frothy sputum results from alveolar flooding with blood-tinged fluid due
to severe pulmonary edema, a hallmark of acute decompensated heart failure. While
ankle edema, JVD, and hepatojugular reflux indicate volume overload and right heart
strain, they are less specific for acute pulmonary edema. Pink frothy sputum signifies
imminent respiratory compromise requiring urgent intervention.
