RELIAS MEDICAL-SURGICAL TELEMETRY
EXAM PREP | 400+ PRACTICE QUESTIONS &
VERIFIED ANSWERS WITH DETAILED
RATIONALES | CARDIAC RHYTHMS, ECG
ANALYSIS & TELEMETRY SUCCESS GUIDE
RELIAS MEDICAL-SURGICAL TELEMETRY EXAM PREP
400+ Practice Questions
Q1. Which layer of the heart is responsible for the actual contraction of the
cardiac muscle?
A. Epicardium B. Pericardium C. Myocardium D. Endocardium E. Visceral pleura
CORRECT ANSWER: C. Myocardium RATIONALE: The myocardium is the
thick muscular middle layer of the heart wall composed of cardiac muscle cells
(cardiomyocytes) responsible for the contractile force of the heart. The epicardium is the
outer layer, the endocardium lines the inner chambers, and the pericardium is the outer
fibrous sac.
Q2. The sinoatrial (SA) node is located in which chamber of the heart?
A. Left ventricle B. Right ventricle C. Left atrium D. Right atrium E. Interventricular
septum
CORRECT ANSWER: D. Right atrium RATIONALE: The SA node is located
in the upper posterior wall of the right atrium near the opening of the superior vena
cava. It is the heart's primary pacemaker, initiating electrical impulses at a rate of 60–
100 beats per minute.
Q3. What is the normal intrinsic firing rate of the atrioventricular (AV) node?
A. 60–100 bpm B. 100–150 bpm C. 40–60 bpm D. 20–40 bpm E. 15–30 bpm
CORRECT ANSWER: C. 40–60 bpm RATIONALE: The AV node has an
intrinsic firing rate of 40–60 bpm. It serves as a backup pacemaker if the SA node fails.
The SA node fires at 60–100 bpm, and ventricular cells fire at 20–40 bpm as the last
resort pacemaker.
,Q4. Which valve separates the left atrium from the left ventricle?
A. Tricuspid valve B. Pulmonic valve C. Aortic valve D. Mitral valve E. Eustachian valve
CORRECT ANSWER: D. Mitral valve RATIONALE: The mitral (bicuspid)
valve has two leaflets and separates the left atrium from the left ventricle. The tricuspid
valve (three leaflets) separates the right atrium from the right ventricle. The aortic and
pulmonic valves are semilunar valves.
Q5. Which coronary artery primarily supplies blood to the left ventricle and
interventricular septum?
A. Right coronary artery (RCA) B. Left anterior descending (LAD) artery C. Right
marginal artery D. Posterior descending artery E. Circumflex artery
CORRECT ANSWER: B. Left anterior descending (LAD) artery
RATIONALE: The LAD artery, a branch of the left main coronary artery, supplies the
anterior wall of the left ventricle, the interventricular septum, and the apex of the heart. It
is often called the "widow maker" because occlusion causes massive MI.
Q6. The Frank-Starling law of the heart states that:
A. Heart rate is inversely proportional to blood pressure B. Cardiac output decreases as
preload increases C. The greater the stretch of cardiac muscle fibers, the greater the
force of contraction D. Afterload is the primary determinant of stroke volume E.
Contractility is independent of fiber length
CORRECT ANSWER: C. The greater the stretch of cardiac muscle fibers, the
greater the force of contraction RATIONALE: The Frank-Starling law states that
the force of ventricular contraction is directly proportional to the end-diastolic volume
(preload). As more blood fills the ventricle, the fibers stretch more, and the subsequent
contraction is stronger — up to a physiologic limit.
Q7. What does cardiac output (CO) represent?
A. The amount of blood ejected per contraction B. The pressure difference between
systole and diastole C. The volume of blood pumped by each ventricle per minute D.
The percentage of blood ejected per beat E. The resistance against which the heart
must pump
, CORRECT ANSWER: C. The volume of blood pumped by each ventricle per
minute RATIONALE: Cardiac output = Heart Rate × Stroke Volume. Normal CO is
4–8 L/min. Stroke volume is the amount ejected per beat (60–100 mL), and heart rate is
beats per minute. This is the fundamental measure of cardiac pump function.
Q8. Which of the following best defines "preload"?
A. The resistance the heart must overcome to eject blood B. The volume of blood in the
ventricle at the end of diastole C. The intrinsic contractility of cardiac muscle D. The
heart rate times stroke volume E. The pressure generated during systole
CORRECT ANSWER: B. The volume of blood in the ventricle at the end of
diastole RATIONALE: Preload refers to the end-diastolic volume (EDV) — the
amount of blood stretching the ventricular walls just before contraction. It is
approximated clinically by central venous pressure (CVP) for right-sided preload and
pulmonary capillary wedge pressure (PCWP) for left-sided preload.
Q9. What is "afterload" in cardiac physiology?
A. The volume of blood returning to the heart B. The force of cardiac muscle contraction
C. The resistance the ventricle must overcome to eject blood D. The oxygen
consumption of the myocardium E. The time between atrial and ventricular contraction
CORRECT ANSWER: C. The resistance the ventricle must overcome to eject
blood RATIONALE: Afterload is the resistance against which the ventricle
contracts to eject blood. For the left ventricle, it is primarily determined by systemic
vascular resistance (SVR). Increased afterload (e.g., hypertension, aortic stenosis)
makes the heart work harder and can reduce stroke volume.
Q10. Which ion is primarily responsible for the rapid depolarization (phase 0) of
the cardiac action potential in non-pacemaker cells?
A. Potassium (K⁺) B. Calcium (Ca²⁺) C. Sodium (Na⁺) D. Chloride (Cl⁻) E. Magnesium
(Mg²⁺)
CORRECT ANSWER: C. Sodium (Na⁺) RATIONALE: Phase 0 (rapid
depolarization) is caused by rapid influx of sodium ions through fast sodium channels.
This occurs in working myocardial cells and Purkinje fibers. Pacemaker cells use slow
calcium channels for depolarization, which is why they depolarize more slowly.
, Q11. What is the normal ejection fraction (EF) of the left ventricle?
A. 20–35% B. 35–50% C. 55–70% D. 70–85% E. 85–100%
CORRECT ANSWER: C. 55–70% RATIONALE: Normal left ventricular
ejection fraction (LVEF) is 55–70%. EF = Stroke Volume ÷ End-Diastolic Volume × 100.
An EF below 40% indicates systolic heart failure. EF is measured by echocardiography
and is a key indicator of cardiac function.
Q12. The Bundle of His divides into which two branches?
A. SA node and AV node B. Left and right bundle branches C. Purkinje fibers and
myocardium D. Internodal pathways and Bachmann's bundle E. Left and right atrial
pathways
CORRECT ANSWER: B. Left and right bundle branches RATIONALE: The
Bundle of His (AV bundle) divides into the left and right bundle branches, which conduct
electrical impulses down the interventricular septum to the Purkinje fibers and then to
the ventricular myocardium, causing simultaneous ventricular contraction.
Q13. Which of the following describes the absolute refractory period of the
cardiac cycle?
A. The period during which the heart can be stimulated with a strong stimulus B. The
period during which the heart cannot be stimulated regardless of stimulus strength C.
The period of rapid repolarization D. The period just before the P wave E. The period
following the T wave
CORRECT ANSWER: B. The period during which the heart cannot be
stimulated regardless of stimulus strength RATIONALE: During the absolute
refractory period (corresponds to the QRS complex and ST segment on ECG), the
cardiac cell cannot respond to any stimulus, no matter how strong. This prevents tetanic
contractions of the heart, which would be fatal. It corresponds to phases 0–3 of the
action potential.
Q14. What does the term "automaticity" mean in cardiac physiology?
EXAM PREP | 400+ PRACTICE QUESTIONS &
VERIFIED ANSWERS WITH DETAILED
RATIONALES | CARDIAC RHYTHMS, ECG
ANALYSIS & TELEMETRY SUCCESS GUIDE
RELIAS MEDICAL-SURGICAL TELEMETRY EXAM PREP
400+ Practice Questions
Q1. Which layer of the heart is responsible for the actual contraction of the
cardiac muscle?
A. Epicardium B. Pericardium C. Myocardium D. Endocardium E. Visceral pleura
CORRECT ANSWER: C. Myocardium RATIONALE: The myocardium is the
thick muscular middle layer of the heart wall composed of cardiac muscle cells
(cardiomyocytes) responsible for the contractile force of the heart. The epicardium is the
outer layer, the endocardium lines the inner chambers, and the pericardium is the outer
fibrous sac.
Q2. The sinoatrial (SA) node is located in which chamber of the heart?
A. Left ventricle B. Right ventricle C. Left atrium D. Right atrium E. Interventricular
septum
CORRECT ANSWER: D. Right atrium RATIONALE: The SA node is located
in the upper posterior wall of the right atrium near the opening of the superior vena
cava. It is the heart's primary pacemaker, initiating electrical impulses at a rate of 60–
100 beats per minute.
Q3. What is the normal intrinsic firing rate of the atrioventricular (AV) node?
A. 60–100 bpm B. 100–150 bpm C. 40–60 bpm D. 20–40 bpm E. 15–30 bpm
CORRECT ANSWER: C. 40–60 bpm RATIONALE: The AV node has an
intrinsic firing rate of 40–60 bpm. It serves as a backup pacemaker if the SA node fails.
The SA node fires at 60–100 bpm, and ventricular cells fire at 20–40 bpm as the last
resort pacemaker.
,Q4. Which valve separates the left atrium from the left ventricle?
A. Tricuspid valve B. Pulmonic valve C. Aortic valve D. Mitral valve E. Eustachian valve
CORRECT ANSWER: D. Mitral valve RATIONALE: The mitral (bicuspid)
valve has two leaflets and separates the left atrium from the left ventricle. The tricuspid
valve (three leaflets) separates the right atrium from the right ventricle. The aortic and
pulmonic valves are semilunar valves.
Q5. Which coronary artery primarily supplies blood to the left ventricle and
interventricular septum?
A. Right coronary artery (RCA) B. Left anterior descending (LAD) artery C. Right
marginal artery D. Posterior descending artery E. Circumflex artery
CORRECT ANSWER: B. Left anterior descending (LAD) artery
RATIONALE: The LAD artery, a branch of the left main coronary artery, supplies the
anterior wall of the left ventricle, the interventricular septum, and the apex of the heart. It
is often called the "widow maker" because occlusion causes massive MI.
Q6. The Frank-Starling law of the heart states that:
A. Heart rate is inversely proportional to blood pressure B. Cardiac output decreases as
preload increases C. The greater the stretch of cardiac muscle fibers, the greater the
force of contraction D. Afterload is the primary determinant of stroke volume E.
Contractility is independent of fiber length
CORRECT ANSWER: C. The greater the stretch of cardiac muscle fibers, the
greater the force of contraction RATIONALE: The Frank-Starling law states that
the force of ventricular contraction is directly proportional to the end-diastolic volume
(preload). As more blood fills the ventricle, the fibers stretch more, and the subsequent
contraction is stronger — up to a physiologic limit.
Q7. What does cardiac output (CO) represent?
A. The amount of blood ejected per contraction B. The pressure difference between
systole and diastole C. The volume of blood pumped by each ventricle per minute D.
The percentage of blood ejected per beat E. The resistance against which the heart
must pump
, CORRECT ANSWER: C. The volume of blood pumped by each ventricle per
minute RATIONALE: Cardiac output = Heart Rate × Stroke Volume. Normal CO is
4–8 L/min. Stroke volume is the amount ejected per beat (60–100 mL), and heart rate is
beats per minute. This is the fundamental measure of cardiac pump function.
Q8. Which of the following best defines "preload"?
A. The resistance the heart must overcome to eject blood B. The volume of blood in the
ventricle at the end of diastole C. The intrinsic contractility of cardiac muscle D. The
heart rate times stroke volume E. The pressure generated during systole
CORRECT ANSWER: B. The volume of blood in the ventricle at the end of
diastole RATIONALE: Preload refers to the end-diastolic volume (EDV) — the
amount of blood stretching the ventricular walls just before contraction. It is
approximated clinically by central venous pressure (CVP) for right-sided preload and
pulmonary capillary wedge pressure (PCWP) for left-sided preload.
Q9. What is "afterload" in cardiac physiology?
A. The volume of blood returning to the heart B. The force of cardiac muscle contraction
C. The resistance the ventricle must overcome to eject blood D. The oxygen
consumption of the myocardium E. The time between atrial and ventricular contraction
CORRECT ANSWER: C. The resistance the ventricle must overcome to eject
blood RATIONALE: Afterload is the resistance against which the ventricle
contracts to eject blood. For the left ventricle, it is primarily determined by systemic
vascular resistance (SVR). Increased afterload (e.g., hypertension, aortic stenosis)
makes the heart work harder and can reduce stroke volume.
Q10. Which ion is primarily responsible for the rapid depolarization (phase 0) of
the cardiac action potential in non-pacemaker cells?
A. Potassium (K⁺) B. Calcium (Ca²⁺) C. Sodium (Na⁺) D. Chloride (Cl⁻) E. Magnesium
(Mg²⁺)
CORRECT ANSWER: C. Sodium (Na⁺) RATIONALE: Phase 0 (rapid
depolarization) is caused by rapid influx of sodium ions through fast sodium channels.
This occurs in working myocardial cells and Purkinje fibers. Pacemaker cells use slow
calcium channels for depolarization, which is why they depolarize more slowly.
, Q11. What is the normal ejection fraction (EF) of the left ventricle?
A. 20–35% B. 35–50% C. 55–70% D. 70–85% E. 85–100%
CORRECT ANSWER: C. 55–70% RATIONALE: Normal left ventricular
ejection fraction (LVEF) is 55–70%. EF = Stroke Volume ÷ End-Diastolic Volume × 100.
An EF below 40% indicates systolic heart failure. EF is measured by echocardiography
and is a key indicator of cardiac function.
Q12. The Bundle of His divides into which two branches?
A. SA node and AV node B. Left and right bundle branches C. Purkinje fibers and
myocardium D. Internodal pathways and Bachmann's bundle E. Left and right atrial
pathways
CORRECT ANSWER: B. Left and right bundle branches RATIONALE: The
Bundle of His (AV bundle) divides into the left and right bundle branches, which conduct
electrical impulses down the interventricular septum to the Purkinje fibers and then to
the ventricular myocardium, causing simultaneous ventricular contraction.
Q13. Which of the following describes the absolute refractory period of the
cardiac cycle?
A. The period during which the heart can be stimulated with a strong stimulus B. The
period during which the heart cannot be stimulated regardless of stimulus strength C.
The period of rapid repolarization D. The period just before the P wave E. The period
following the T wave
CORRECT ANSWER: B. The period during which the heart cannot be
stimulated regardless of stimulus strength RATIONALE: During the absolute
refractory period (corresponds to the QRS complex and ST segment on ECG), the
cardiac cell cannot respond to any stimulus, no matter how strong. This prevents tetanic
contractions of the heart, which would be fatal. It corresponds to phases 0–3 of the
action potential.
Q14. What does the term "automaticity" mean in cardiac physiology?
