CET EKG Rhythm Interpretation Practice Exam Study Guide Updated 2026
/ Verified Questions and Answers with Detailed Rationales | ECG
Waveform Analysis (P, QRS, T), Cardiac Conduction System, Normal Sinus
Rhythm Identification, Dysrhythmias (Atrial Fibrillation, Atrial Flutter,
Ventricular Tachycardia, Ventricular Fibrillation, Heart Blocks), Rate and
Rhythm Calculation Methods, 12-Lead ECG Basics, Axis Determination,
Artifact Recognition, ACLS Correlation, Clinical Scenario-Based Questions
| Complete Exam Prep Resource for CET Certification Success
Question 1: Which EKG finding is most characteristic of normal sinus rhythm?
A. Irregularly irregular R-R intervals with absent P waves
B. Regular rhythm with upright P waves in lead II preceding each QRS complex
C. Wide QRS complexes greater than 0.12 seconds with no visible P waves
D. Sawtooth flutter waves at 300 beats per minute in lead II
CORRECT ANSWER: B. Regular rhythm with upright P waves in lead II preceding
each QRS complex
RATIONALE: Normal sinus rhythm is defined by a regular rhythm originating from the
sinoatrial node, with upright P waves in lead II indicating proper atrial depolarization, a
PR interval of 0.12-0.20 seconds, and each P wave followed by a QRS complex. This
distinguishes it from arrhythmias like atrial fibrillation or ventricular rhythms.
Question 2: A patient's EKG shows a heart rate of 48 bpm, regular rhythm, normal P
waves, and a PR interval of 0.16 seconds. What is the most appropriate rhythm
interpretation?
A. Sinus tachycardia
B. Junctional escape rhythm
C. Sinus bradycardia
D. First-degree AV block
CORRECT ANSWER: C. Sinus bradycardia
RATIONALE: Sinus bradycardia is characterized by a sinus rhythm with a heart rate
below 60 bpm in adults. The presence of normal P waves, consistent PR interval, and
regular rhythm confirms the impulse originates from the SA node, distinguishing it from
junctional rhythms or heart blocks.
Question 3: Which feature is diagnostic of atrial fibrillation on a 12-lead EKG?
A. Regular atrial activity at 250-350 bpm with sawtooth waves
B. Absent P waves with an irregularly irregular ventricular response
C. Prolonged PR interval greater than 0.20 seconds with consistent P:QRS ratio
D. Wide QRS complexes with AV dissociation
CORRECT ANSWER: B. Absent P waves with an irregularly irregular ventricular
response
,CET EKG Rhythm Interpretation Practice Exam Study Guide Updated 2026
/ Verified Questions and Answers with Detailed Rationales | ECG
Waveform Analysis (P, QRS, T), Cardiac Conduction System, Normal Sinus
Rhythm Identification, Dysrhythmias (Atrial Fibrillation, Atrial Flutter,
Ventricular Tachycardia, Ventricular Fibrillation, Heart Blocks), Rate and
Rhythm Calculation Methods, 12-Lead ECG Basics, Axis Determination,
Artifact Recognition, ACLS Correlation, Clinical Scenario-Based Questions
| Complete Exam Prep Resource for CET Certification Success
RATIONALE: Atrial fibrillation is identified by the absence of distinct P waves due to
chaotic atrial depolarization, replaced by fibrillatory waves, and an irregularly irregular
ventricular rhythm resulting from variable AV nodal conduction. This differentiates it
from atrial flutter or other supraventricular arrhythmias.
Question 4: In second-degree AV block type I (Wenckebach), what pattern is
observed on the EKG?
A. Constant PR interval with occasional non-conducted P waves
B. Progressively lengthening PR intervals until a P wave is not conducted
C. Fixed 2:1 or 3:1 conduction ratio with normal PR intervals
D. Complete dissociation between P waves and QRS complexes
CORRECT ANSWER: B. Progressively lengthening PR intervals until a P wave is not
conducted
RATIONALE: Wenckebach phenomenon features progressive prolongation of the PR
interval with each beat until a P wave fails to conduct to the ventricles, after which the
cycle repeats. This reflects decremental conduction in the AV node and is typically
benign compared to type II block.
Question 5: Which EKG finding is most suggestive of ventricular tachycardia rather
than supraventricular tachycardia with aberrancy?
A. Narrow QRS complexes less than 0.10 seconds
B. AV dissociation with capture or fusion beats
C. Typical right bundle branch block morphology
D. Heart rate of 180 bpm with visible P waves before each QRS
CORRECT ANSWER: B. AV dissociation with capture or fusion beats
RATIONALE: AV dissociation, where P waves march through the QRS complexes
independently, along with capture or fusion beats, is highly specific for ventricular
tachycardia. This occurs because the ventricles are depolarized independently of atrial
activity, a hallmark of VT versus SVT with aberrant conduction.
Question 6: A patient presents with a heart rate of 150 bpm, regular rhythm, and
sawtooth flutter waves best seen in leads II, III, and aVF. What is the rhythm?
,CET EKG Rhythm Interpretation Practice Exam Study Guide Updated 2026
/ Verified Questions and Answers with Detailed Rationales | ECG
Waveform Analysis (P, QRS, T), Cardiac Conduction System, Normal Sinus
Rhythm Identification, Dysrhythmias (Atrial Fibrillation, Atrial Flutter,
Ventricular Tachycardia, Ventricular Fibrillation, Heart Blocks), Rate and
Rhythm Calculation Methods, 12-Lead ECG Basics, Axis Determination,
Artifact Recognition, ACLS Correlation, Clinical Scenario-Based Questions
| Complete Exam Prep Resource for CET Certification Success
A. Atrial fibrillation with rapid ventricular response
B. Sinus tachycardia
C. Atrial flutter with 2:1 conduction
D. Multifocal atrial tachycardia
CORRECT ANSWER: C. Atrial flutter with 2:1 conduction
RATIONALE: Atrial flutter typically shows regular atrial activity at 250-350 bpm with
characteristic sawtooth flutter waves, most prominent in inferior leads. With 2:1 AV
conduction, the ventricular rate is approximately 150 bpm, which is a common
presentation. This distinguishes it from atrial fibrillation or sinus tachycardia.
Question 7: Which EKG interval represents the time from the beginning of atrial
depolarization to the beginning of ventricular depolarization?
A. QT interval
B. ST segment
C. PR interval
D. QRS duration
CORRECT ANSWER: C. PR interval
RATIONALE: The PR interval measures conduction time from the SA node through the
atria, AV node, and His-Purkinje system to the onset of ventricular depolarization. It
normally ranges from 0.12 to 0.20 seconds; prolongation indicates AV conduction delay.
Question 8: What is the hallmark EKG feature of third-degree (complete) AV block?
A. Progressive PR prolongation until a dropped beat
B. Constant PR interval with intermittent non-conducted P waves
C. Complete AV dissociation with independent atrial and ventricular rates
D. Inverted P waves following the QRS complex
CORRECT ANSWER: C. Complete AV dissociation with independent atrial and
ventricular rates
RATIONALE: In complete heart block, there is no conduction between atria and
ventricles, resulting in independent rhythms: atrial rate (P waves) is faster than
ventricular escape rate (QRS complexes), with no relationship between them. This
requires urgent evaluation for pacemaker placement.
, CET EKG Rhythm Interpretation Practice Exam Study Guide Updated 2026
/ Verified Questions and Answers with Detailed Rationales | ECG
Waveform Analysis (P, QRS, T), Cardiac Conduction System, Normal Sinus
Rhythm Identification, Dysrhythmias (Atrial Fibrillation, Atrial Flutter,
Ventricular Tachycardia, Ventricular Fibrillation, Heart Blocks), Rate and
Rhythm Calculation Methods, 12-Lead ECG Basics, Axis Determination,
Artifact Recognition, ACLS Correlation, Clinical Scenario-Based Questions
| Complete Exam Prep Resource for CET Certification Success
Question 9: Which finding on EKG is most consistent with a premature ventricular
contraction (PVC)?
A. Early P wave with abnormal morphology followed by normal QRS
B. Wide, bizarre QRS complex greater than 0.12 seconds without preceding P wave
C. Shortened PR interval with delta wave
D. Regular rhythm with inverted P waves in lead II
CORRECT ANSWER: B. Wide, bizarre QRS complex greater than 0.12 seconds
without preceding P wave
RATIONALE: PVCs originate in the ventricles, producing a wide, abnormal QRS complex
(>0.12 sec) without a preceding P wave, often followed by a compensatory pause. The
morphology differs from sinus beats due to abnormal ventricular depolarization
sequence.
Question 10: A patient's EKG shows a regular rhythm at 40 bpm, narrow QRS
complexes, and inverted P waves in lead II occurring after the QRS. What rhythm is
this?
A. Sinus bradycardia
B. Junctional escape rhythm
C. Idioventricular rhythm
D. Atrial fibrillation with slow ventricular response
CORRECT ANSWER: B. Junctional escape rhythm
RATIONALE: Junctional rhythms originate from the AV junction, producing narrow QRS
complexes (unless aberrant) at 40-60 bpm. Inverted P waves in lead II may appear
before, during, or after the QRS depending on retrograde atrial conduction timing,
distinguishing it from sinus or ventricular rhythms.
Question 11: Which EKG change is most specific for acute anterior wall myocardial
infarction?
A. ST depression in leads V1-V4
B. ST elevation in leads V1-V4 with reciprocal changes
C. T wave inversion in leads II, III, aVF
D. Prolonged QT interval with U waves
/ Verified Questions and Answers with Detailed Rationales | ECG
Waveform Analysis (P, QRS, T), Cardiac Conduction System, Normal Sinus
Rhythm Identification, Dysrhythmias (Atrial Fibrillation, Atrial Flutter,
Ventricular Tachycardia, Ventricular Fibrillation, Heart Blocks), Rate and
Rhythm Calculation Methods, 12-Lead ECG Basics, Axis Determination,
Artifact Recognition, ACLS Correlation, Clinical Scenario-Based Questions
| Complete Exam Prep Resource for CET Certification Success
Question 1: Which EKG finding is most characteristic of normal sinus rhythm?
A. Irregularly irregular R-R intervals with absent P waves
B. Regular rhythm with upright P waves in lead II preceding each QRS complex
C. Wide QRS complexes greater than 0.12 seconds with no visible P waves
D. Sawtooth flutter waves at 300 beats per minute in lead II
CORRECT ANSWER: B. Regular rhythm with upright P waves in lead II preceding
each QRS complex
RATIONALE: Normal sinus rhythm is defined by a regular rhythm originating from the
sinoatrial node, with upright P waves in lead II indicating proper atrial depolarization, a
PR interval of 0.12-0.20 seconds, and each P wave followed by a QRS complex. This
distinguishes it from arrhythmias like atrial fibrillation or ventricular rhythms.
Question 2: A patient's EKG shows a heart rate of 48 bpm, regular rhythm, normal P
waves, and a PR interval of 0.16 seconds. What is the most appropriate rhythm
interpretation?
A. Sinus tachycardia
B. Junctional escape rhythm
C. Sinus bradycardia
D. First-degree AV block
CORRECT ANSWER: C. Sinus bradycardia
RATIONALE: Sinus bradycardia is characterized by a sinus rhythm with a heart rate
below 60 bpm in adults. The presence of normal P waves, consistent PR interval, and
regular rhythm confirms the impulse originates from the SA node, distinguishing it from
junctional rhythms or heart blocks.
Question 3: Which feature is diagnostic of atrial fibrillation on a 12-lead EKG?
A. Regular atrial activity at 250-350 bpm with sawtooth waves
B. Absent P waves with an irregularly irregular ventricular response
C. Prolonged PR interval greater than 0.20 seconds with consistent P:QRS ratio
D. Wide QRS complexes with AV dissociation
CORRECT ANSWER: B. Absent P waves with an irregularly irregular ventricular
response
,CET EKG Rhythm Interpretation Practice Exam Study Guide Updated 2026
/ Verified Questions and Answers with Detailed Rationales | ECG
Waveform Analysis (P, QRS, T), Cardiac Conduction System, Normal Sinus
Rhythm Identification, Dysrhythmias (Atrial Fibrillation, Atrial Flutter,
Ventricular Tachycardia, Ventricular Fibrillation, Heart Blocks), Rate and
Rhythm Calculation Methods, 12-Lead ECG Basics, Axis Determination,
Artifact Recognition, ACLS Correlation, Clinical Scenario-Based Questions
| Complete Exam Prep Resource for CET Certification Success
RATIONALE: Atrial fibrillation is identified by the absence of distinct P waves due to
chaotic atrial depolarization, replaced by fibrillatory waves, and an irregularly irregular
ventricular rhythm resulting from variable AV nodal conduction. This differentiates it
from atrial flutter or other supraventricular arrhythmias.
Question 4: In second-degree AV block type I (Wenckebach), what pattern is
observed on the EKG?
A. Constant PR interval with occasional non-conducted P waves
B. Progressively lengthening PR intervals until a P wave is not conducted
C. Fixed 2:1 or 3:1 conduction ratio with normal PR intervals
D. Complete dissociation between P waves and QRS complexes
CORRECT ANSWER: B. Progressively lengthening PR intervals until a P wave is not
conducted
RATIONALE: Wenckebach phenomenon features progressive prolongation of the PR
interval with each beat until a P wave fails to conduct to the ventricles, after which the
cycle repeats. This reflects decremental conduction in the AV node and is typically
benign compared to type II block.
Question 5: Which EKG finding is most suggestive of ventricular tachycardia rather
than supraventricular tachycardia with aberrancy?
A. Narrow QRS complexes less than 0.10 seconds
B. AV dissociation with capture or fusion beats
C. Typical right bundle branch block morphology
D. Heart rate of 180 bpm with visible P waves before each QRS
CORRECT ANSWER: B. AV dissociation with capture or fusion beats
RATIONALE: AV dissociation, where P waves march through the QRS complexes
independently, along with capture or fusion beats, is highly specific for ventricular
tachycardia. This occurs because the ventricles are depolarized independently of atrial
activity, a hallmark of VT versus SVT with aberrant conduction.
Question 6: A patient presents with a heart rate of 150 bpm, regular rhythm, and
sawtooth flutter waves best seen in leads II, III, and aVF. What is the rhythm?
,CET EKG Rhythm Interpretation Practice Exam Study Guide Updated 2026
/ Verified Questions and Answers with Detailed Rationales | ECG
Waveform Analysis (P, QRS, T), Cardiac Conduction System, Normal Sinus
Rhythm Identification, Dysrhythmias (Atrial Fibrillation, Atrial Flutter,
Ventricular Tachycardia, Ventricular Fibrillation, Heart Blocks), Rate and
Rhythm Calculation Methods, 12-Lead ECG Basics, Axis Determination,
Artifact Recognition, ACLS Correlation, Clinical Scenario-Based Questions
| Complete Exam Prep Resource for CET Certification Success
A. Atrial fibrillation with rapid ventricular response
B. Sinus tachycardia
C. Atrial flutter with 2:1 conduction
D. Multifocal atrial tachycardia
CORRECT ANSWER: C. Atrial flutter with 2:1 conduction
RATIONALE: Atrial flutter typically shows regular atrial activity at 250-350 bpm with
characteristic sawtooth flutter waves, most prominent in inferior leads. With 2:1 AV
conduction, the ventricular rate is approximately 150 bpm, which is a common
presentation. This distinguishes it from atrial fibrillation or sinus tachycardia.
Question 7: Which EKG interval represents the time from the beginning of atrial
depolarization to the beginning of ventricular depolarization?
A. QT interval
B. ST segment
C. PR interval
D. QRS duration
CORRECT ANSWER: C. PR interval
RATIONALE: The PR interval measures conduction time from the SA node through the
atria, AV node, and His-Purkinje system to the onset of ventricular depolarization. It
normally ranges from 0.12 to 0.20 seconds; prolongation indicates AV conduction delay.
Question 8: What is the hallmark EKG feature of third-degree (complete) AV block?
A. Progressive PR prolongation until a dropped beat
B. Constant PR interval with intermittent non-conducted P waves
C. Complete AV dissociation with independent atrial and ventricular rates
D. Inverted P waves following the QRS complex
CORRECT ANSWER: C. Complete AV dissociation with independent atrial and
ventricular rates
RATIONALE: In complete heart block, there is no conduction between atria and
ventricles, resulting in independent rhythms: atrial rate (P waves) is faster than
ventricular escape rate (QRS complexes), with no relationship between them. This
requires urgent evaluation for pacemaker placement.
, CET EKG Rhythm Interpretation Practice Exam Study Guide Updated 2026
/ Verified Questions and Answers with Detailed Rationales | ECG
Waveform Analysis (P, QRS, T), Cardiac Conduction System, Normal Sinus
Rhythm Identification, Dysrhythmias (Atrial Fibrillation, Atrial Flutter,
Ventricular Tachycardia, Ventricular Fibrillation, Heart Blocks), Rate and
Rhythm Calculation Methods, 12-Lead ECG Basics, Axis Determination,
Artifact Recognition, ACLS Correlation, Clinical Scenario-Based Questions
| Complete Exam Prep Resource for CET Certification Success
Question 9: Which finding on EKG is most consistent with a premature ventricular
contraction (PVC)?
A. Early P wave with abnormal morphology followed by normal QRS
B. Wide, bizarre QRS complex greater than 0.12 seconds without preceding P wave
C. Shortened PR interval with delta wave
D. Regular rhythm with inverted P waves in lead II
CORRECT ANSWER: B. Wide, bizarre QRS complex greater than 0.12 seconds
without preceding P wave
RATIONALE: PVCs originate in the ventricles, producing a wide, abnormal QRS complex
(>0.12 sec) without a preceding P wave, often followed by a compensatory pause. The
morphology differs from sinus beats due to abnormal ventricular depolarization
sequence.
Question 10: A patient's EKG shows a regular rhythm at 40 bpm, narrow QRS
complexes, and inverted P waves in lead II occurring after the QRS. What rhythm is
this?
A. Sinus bradycardia
B. Junctional escape rhythm
C. Idioventricular rhythm
D. Atrial fibrillation with slow ventricular response
CORRECT ANSWER: B. Junctional escape rhythm
RATIONALE: Junctional rhythms originate from the AV junction, producing narrow QRS
complexes (unless aberrant) at 40-60 bpm. Inverted P waves in lead II may appear
before, during, or after the QRS depending on retrograde atrial conduction timing,
distinguishing it from sinus or ventricular rhythms.
Question 11: Which EKG change is most specific for acute anterior wall myocardial
infarction?
A. ST depression in leads V1-V4
B. ST elevation in leads V1-V4 with reciprocal changes
C. T wave inversion in leads II, III, aVF
D. Prolonged QT interval with U waves
