Relias Dysrhythmia Basic A Test — Practice
Exam 2026–2027
Original Study Guide with Overview and 60 Practice Questions & Answers
This study guide is an original, independently created resource designed to help learners prepare for a basic
dysrhythmia competency assessment. It is not affiliated with, endorsed by, or reproduced from Relias LLC or any
proprietary examination. All questions and content in this guide were written from general dysrhythmia recognition
principles for educational review purposes.
Section 1: Exam Overview
1. Purpose of a Basic Dysrhythmia Examination
A basic dysrhythmia examination evaluates a clinician's ability to identify common cardiac rhythms from a monitor
strip or 12-lead ECG, recognize when a rhythm is clinically significant, and determine an appropriate initial
response. These competencies support safe patient monitoring in telemetry, critical care, emergency, and general
medical-surgical settings.
2. ECG/EKG Fundamentals
The ECG records the heart's electrical activity as it travels through the conduction system: SA node → atria → AV
node → bundle of His → bundle branches → Purkinje fibers → ventricular myocardium. Each deflection on the
tracing corresponds to a specific phase of this electrical cycle. Understanding the normal sequence and timing of
these deflections is the foundation for recognizing abnormal rhythms.
3. Normal ECG Components
• P wave — atrial depolarization
• PR interval — time from the start of atrial depolarization to the start of ventricular depolarization (normal:
0.12–0.20 seconds)
• QRS complex — ventricular depolarization (normal duration: 0.06–0.10 seconds, up to 0.12 seconds)
• ST segment — the isoelectric period between depolarization and repolarization of the ventricles
• T wave — ventricular repolarization
• QT interval — total duration of ventricular depolarization and repolarization; varies with heart rate
4. Normal Adult Heart Rate and Rhythm Characteristics
A normal adult resting heart rate falls between 60 and 100 beats per minute, with a regular rhythm, one upright P
wave preceding each QRS complex, a consistent PR interval, and a narrow QRS complex. Deviations in rate,
regularity, or the relationship between P waves and QRS complexes point toward a specific dysrhythmia.
5. How to Determine Key ECG Characteristics
• Heart rate: use the 6-second method (count QRS complexes in a 6-second strip × 10) or the 300 method (300 ÷
number of large boxes between R waves) for regular rhythms
• Rhythm regularity: compare R-to-R intervals across the strip; consistent intervals = regular, variable intervals
= irregular
, • P-wave characteristics: assess presence, shape, and consistency — one uniform upright P wave before each
QRS suggests a sinus origin
• PR interval: measure from the start of the P wave to the start of the QRS complex; normal is 0.12–0.20
seconds
• QRS duration: measure from the start to the end of the QRS complex; normal is under 0.12 seconds
6. Basic ECG Interpretation Approach
A systematic, repeatable method prevents missed findings: (1) determine the rate, (2) assess rhythm regularity, (3)
evaluate P waves, (4) measure the PR interval, (5) measure the QRS duration, and (6) determine the relationship
between P waves and QRS complexes. Applying these steps in order to every strip builds consistency and accuracy.
7. Sinus Rhythms
Sinus rhythms originate in the SA node and include normal sinus rhythm, sinus bradycardia (rate under 60), sinus
tachycardia (rate over 100), and sinus arrhythmia (rate varies with respiration). All sinus rhythms share the defining
feature of a normal, upright P wave preceding each QRS with a consistent PR interval.
8. Atrial Dysrhythmias
Atrial dysrhythmias originate from ectopic foci or reentrant circuits within the atria, outside the SA node. This
category includes premature atrial contractions (PACs), atrial fibrillation, atrial flutter, and supraventricular
tachycardia (SVT). These rhythms are often recognized by abnormal P-wave morphology, absent P waves, or a
chaotic/sawtooth atrial baseline.
9. Junctional Rhythms
Junctional rhythms originate in the AV junction when it takes over pacemaker function, either because the SA node
fails or as an accelerated/ectopic focus. P waves may be absent, inverted, or occur in an abnormal relationship to the
QRS (before, hidden within, or after), while the QRS itself typically remains narrow.
10. Ventricular Dysrhythmias
Ventricular dysrhythmias originate below the AV junction, within the ventricular myocardium or conduction
system. This category ranges from isolated premature ventricular contractions (PVCs) to life-threatening rhythms
such as ventricular tachycardia, torsades de pointes, and ventricular fibrillation. Ventricular rhythms are
characterized by wide, often bizarre QRS complexes.
11. AV Conduction Blocks
AV blocks reflect delayed or interrupted conduction between the atria and ventricles, ranging from first-degree (a
simple delay) through second-degree Type I and Type II (intermittent dropped beats) to third-degree/complete heart
block (total dissociation between atrial and ventricular activity).
12. Common Causes and Clinical Significance
Dysrhythmias can result from structural heart disease, ischemia, electrolyte imbalances (particularly potassium,
calcium, and magnesium), medication effects, autonomic tone changes, hypoxia, and conduction system disease.
Clinical significance depends less on the rhythm name alone and more on its effect on the patient's hemodynamic
stability and symptoms.
13. Basic Nursing and Clinical Priorities
, • Always correlate the rhythm with the patient — assess for symptoms, vital signs, and level of consciousness
rather than treating the strip in isolation
• Distinguish stable from unstable presentations, since this drives the urgency of intervention
• Recognize which rhythms are emergencies (pulseless VT, VFib, symptomatic bradycardia, unstable
tachycardia) versus which typically warrant monitoring and provider notification
• Document rhythm changes, frequency of ectopy, and any associated symptoms accurately and promptly
Quick Recognition Guide
Clue on the strip Think of...
Regular, normal P before each QRS, rate 60–100 Normal sinus rhythm
Same as above, but rate < 60 or > 100 Sinus bradycardia / sinus tachycardia
Rate varies with breathing Sinus arrhythmia
Irregularly irregular, no true P waves Atrial fibrillation
Sawtooth atrial waves, regular ventricular rate Atrial flutter
Narrow, regular, very fast (150–250), P waves hidden SVT
Narrow QRS, absent/inverted P waves, rate 40–60 Junctional escape rhythm
PR gets longer, then a beat drops (repeating pattern) Mobitz I (Wenckebach)
Constant PR, sudden dropped beat, no warning Mobitz II
P waves and QRS totally independent of each other Third-degree (complete) block
Early, wide, bizarre QRS, no preceding P PVC
3+ wide QRS in a row, rate > 100 Ventricular tachycardia
Wide QRS rhythm that appears to twist around baseline Torsades de pointes
Chaotic, no organized complexes, pulseless Ventricular fibrillation
Exam 2026–2027
Original Study Guide with Overview and 60 Practice Questions & Answers
This study guide is an original, independently created resource designed to help learners prepare for a basic
dysrhythmia competency assessment. It is not affiliated with, endorsed by, or reproduced from Relias LLC or any
proprietary examination. All questions and content in this guide were written from general dysrhythmia recognition
principles for educational review purposes.
Section 1: Exam Overview
1. Purpose of a Basic Dysrhythmia Examination
A basic dysrhythmia examination evaluates a clinician's ability to identify common cardiac rhythms from a monitor
strip or 12-lead ECG, recognize when a rhythm is clinically significant, and determine an appropriate initial
response. These competencies support safe patient monitoring in telemetry, critical care, emergency, and general
medical-surgical settings.
2. ECG/EKG Fundamentals
The ECG records the heart's electrical activity as it travels through the conduction system: SA node → atria → AV
node → bundle of His → bundle branches → Purkinje fibers → ventricular myocardium. Each deflection on the
tracing corresponds to a specific phase of this electrical cycle. Understanding the normal sequence and timing of
these deflections is the foundation for recognizing abnormal rhythms.
3. Normal ECG Components
• P wave — atrial depolarization
• PR interval — time from the start of atrial depolarization to the start of ventricular depolarization (normal:
0.12–0.20 seconds)
• QRS complex — ventricular depolarization (normal duration: 0.06–0.10 seconds, up to 0.12 seconds)
• ST segment — the isoelectric period between depolarization and repolarization of the ventricles
• T wave — ventricular repolarization
• QT interval — total duration of ventricular depolarization and repolarization; varies with heart rate
4. Normal Adult Heart Rate and Rhythm Characteristics
A normal adult resting heart rate falls between 60 and 100 beats per minute, with a regular rhythm, one upright P
wave preceding each QRS complex, a consistent PR interval, and a narrow QRS complex. Deviations in rate,
regularity, or the relationship between P waves and QRS complexes point toward a specific dysrhythmia.
5. How to Determine Key ECG Characteristics
• Heart rate: use the 6-second method (count QRS complexes in a 6-second strip × 10) or the 300 method (300 ÷
number of large boxes between R waves) for regular rhythms
• Rhythm regularity: compare R-to-R intervals across the strip; consistent intervals = regular, variable intervals
= irregular
, • P-wave characteristics: assess presence, shape, and consistency — one uniform upright P wave before each
QRS suggests a sinus origin
• PR interval: measure from the start of the P wave to the start of the QRS complex; normal is 0.12–0.20
seconds
• QRS duration: measure from the start to the end of the QRS complex; normal is under 0.12 seconds
6. Basic ECG Interpretation Approach
A systematic, repeatable method prevents missed findings: (1) determine the rate, (2) assess rhythm regularity, (3)
evaluate P waves, (4) measure the PR interval, (5) measure the QRS duration, and (6) determine the relationship
between P waves and QRS complexes. Applying these steps in order to every strip builds consistency and accuracy.
7. Sinus Rhythms
Sinus rhythms originate in the SA node and include normal sinus rhythm, sinus bradycardia (rate under 60), sinus
tachycardia (rate over 100), and sinus arrhythmia (rate varies with respiration). All sinus rhythms share the defining
feature of a normal, upright P wave preceding each QRS with a consistent PR interval.
8. Atrial Dysrhythmias
Atrial dysrhythmias originate from ectopic foci or reentrant circuits within the atria, outside the SA node. This
category includes premature atrial contractions (PACs), atrial fibrillation, atrial flutter, and supraventricular
tachycardia (SVT). These rhythms are often recognized by abnormal P-wave morphology, absent P waves, or a
chaotic/sawtooth atrial baseline.
9. Junctional Rhythms
Junctional rhythms originate in the AV junction when it takes over pacemaker function, either because the SA node
fails or as an accelerated/ectopic focus. P waves may be absent, inverted, or occur in an abnormal relationship to the
QRS (before, hidden within, or after), while the QRS itself typically remains narrow.
10. Ventricular Dysrhythmias
Ventricular dysrhythmias originate below the AV junction, within the ventricular myocardium or conduction
system. This category ranges from isolated premature ventricular contractions (PVCs) to life-threatening rhythms
such as ventricular tachycardia, torsades de pointes, and ventricular fibrillation. Ventricular rhythms are
characterized by wide, often bizarre QRS complexes.
11. AV Conduction Blocks
AV blocks reflect delayed or interrupted conduction between the atria and ventricles, ranging from first-degree (a
simple delay) through second-degree Type I and Type II (intermittent dropped beats) to third-degree/complete heart
block (total dissociation between atrial and ventricular activity).
12. Common Causes and Clinical Significance
Dysrhythmias can result from structural heart disease, ischemia, electrolyte imbalances (particularly potassium,
calcium, and magnesium), medication effects, autonomic tone changes, hypoxia, and conduction system disease.
Clinical significance depends less on the rhythm name alone and more on its effect on the patient's hemodynamic
stability and symptoms.
13. Basic Nursing and Clinical Priorities
, • Always correlate the rhythm with the patient — assess for symptoms, vital signs, and level of consciousness
rather than treating the strip in isolation
• Distinguish stable from unstable presentations, since this drives the urgency of intervention
• Recognize which rhythms are emergencies (pulseless VT, VFib, symptomatic bradycardia, unstable
tachycardia) versus which typically warrant monitoring and provider notification
• Document rhythm changes, frequency of ectopy, and any associated symptoms accurately and promptly
Quick Recognition Guide
Clue on the strip Think of...
Regular, normal P before each QRS, rate 60–100 Normal sinus rhythm
Same as above, but rate < 60 or > 100 Sinus bradycardia / sinus tachycardia
Rate varies with breathing Sinus arrhythmia
Irregularly irregular, no true P waves Atrial fibrillation
Sawtooth atrial waves, regular ventricular rate Atrial flutter
Narrow, regular, very fast (150–250), P waves hidden SVT
Narrow QRS, absent/inverted P waves, rate 40–60 Junctional escape rhythm
PR gets longer, then a beat drops (repeating pattern) Mobitz I (Wenckebach)
Constant PR, sudden dropped beat, no warning Mobitz II
P waves and QRS totally independent of each other Third-degree (complete) block
Early, wide, bizarre QRS, no preceding P PVC
3+ wide QRS in a row, rate > 100 Ventricular tachycardia
Wide QRS rhythm that appears to twist around baseline Torsades de pointes
Chaotic, no organized complexes, pulseless Ventricular fibrillation
