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HCA Healthcare Telemetry ECG/EKG Interpretation Exam
Comprehensive Practice Question Bank 150 Multiple-Choice
Questions with Verified Answers and Detailed Rationales
Aligned with HCA Telemetry Competency Standards & AHA
2025/2026 Guidelines
SECTION 1: CARDIAC ELECTROPHYSIOLOGY FUNDAMENTALS (Questions 1–20)
Question 1
The sinoatrial (SA) node is located in which chamber of the heart and serves as the primary
pacemaker?
• A) Left atrium, near the pulmonary veins
• B) Right atrium, near the superior vena cava
• C) Right ventricle, near the interventricular septum
• D) Left ventricle, near the apex
Correct Answer: B
Rationale: The SA node is located in the upper wall of the right atrium near the opening of the
superior vena cava. It is the heart's natural pacemaker, generating electrical impulses that
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initiate each cardiac cycle. The SA node typically fires at 60–100 beats per minute in a resting
adult.
Question 2
What is the normal intrinsic firing rate of the atrioventricular (AV) node when it functions as the
escape pacemaker?
• A) 60–100 beats per minute
• B) 40–60 beats per minute
• C) 20–40 beats per minute
• D) 100–150 beats per minute
Correct Answer: B
Rationale: The AV node has an intrinsic firing rate of 40–60 beats per minute. It serves as the
secondary pacemaker when the SA node fails or when conduction from the SA node is blocked.
The ventricular Purkinje fibers have the slowest intrinsic rate at 20–40 bpm.
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Question 3
Which phase of the cardiac action potential corresponds to rapid ventricular depolarization and
is represented by the QRS complex on the ECG?
• A) Phase 0
• B) Phase 1
• C) Phase 2
• D) Phase 3
Correct Answer: A
Rationale: Phase 0 of the action potential represents rapid depolarization caused by the influx
of sodium ions through fast sodium channels. This phase corresponds to the QRS complex on
the surface ECG. Phase 2 is the plateau phase (ST segment), and Phase 3 is repolarization (T
wave).
Question 4
The PR interval on a standard ECG represents which physiological event?
• A) Time from ventricular depolarization to ventricular repolarization
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• B) Time from atrial depolarization to the beginning of ventricular depolarization
• C) Time required for complete ventricular repolarization
• D) Time from SA node firing to complete atrial depolarization
Correct Answer: B
Rationale: The PR interval measures the time from the onset of atrial depolarization (P wave) to
the onset of ventricular depolarization (QRS complex). It reflects conduction through the atria,
AV node, and His-Purkinje system. Normal PR interval is 0.12–0.20 seconds (120–200 ms).
Question 5
Which component of the ECG reflects the time required for the ventricles to repolarize?
• A) PR interval
• B) QRS duration
• C) QT interval
• D) ST segment
Correct Answer: C
HCA Healthcare Telemetry ECG/EKG Interpretation Exam
Comprehensive Practice Question Bank 150 Multiple-Choice
Questions with Verified Answers and Detailed Rationales
Aligned with HCA Telemetry Competency Standards & AHA
2025/2026 Guidelines
SECTION 1: CARDIAC ELECTROPHYSIOLOGY FUNDAMENTALS (Questions 1–20)
Question 1
The sinoatrial (SA) node is located in which chamber of the heart and serves as the primary
pacemaker?
• A) Left atrium, near the pulmonary veins
• B) Right atrium, near the superior vena cava
• C) Right ventricle, near the interventricular septum
• D) Left ventricle, near the apex
Correct Answer: B
Rationale: The SA node is located in the upper wall of the right atrium near the opening of the
superior vena cava. It is the heart's natural pacemaker, generating electrical impulses that
,2
initiate each cardiac cycle. The SA node typically fires at 60–100 beats per minute in a resting
adult.
Question 2
What is the normal intrinsic firing rate of the atrioventricular (AV) node when it functions as the
escape pacemaker?
• A) 60–100 beats per minute
• B) 40–60 beats per minute
• C) 20–40 beats per minute
• D) 100–150 beats per minute
Correct Answer: B
Rationale: The AV node has an intrinsic firing rate of 40–60 beats per minute. It serves as the
secondary pacemaker when the SA node fails or when conduction from the SA node is blocked.
The ventricular Purkinje fibers have the slowest intrinsic rate at 20–40 bpm.
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Question 3
Which phase of the cardiac action potential corresponds to rapid ventricular depolarization and
is represented by the QRS complex on the ECG?
• A) Phase 0
• B) Phase 1
• C) Phase 2
• D) Phase 3
Correct Answer: A
Rationale: Phase 0 of the action potential represents rapid depolarization caused by the influx
of sodium ions through fast sodium channels. This phase corresponds to the QRS complex on
the surface ECG. Phase 2 is the plateau phase (ST segment), and Phase 3 is repolarization (T
wave).
Question 4
The PR interval on a standard ECG represents which physiological event?
• A) Time from ventricular depolarization to ventricular repolarization
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• B) Time from atrial depolarization to the beginning of ventricular depolarization
• C) Time required for complete ventricular repolarization
• D) Time from SA node firing to complete atrial depolarization
Correct Answer: B
Rationale: The PR interval measures the time from the onset of atrial depolarization (P wave) to
the onset of ventricular depolarization (QRS complex). It reflects conduction through the atria,
AV node, and His-Purkinje system. Normal PR interval is 0.12–0.20 seconds (120–200 ms).
Question 5
Which component of the ECG reflects the time required for the ventricles to repolarize?
• A) PR interval
• B) QRS duration
• C) QT interval
• D) ST segment
Correct Answer: C
