Relias Dysrhythmia Basic A –
2025/2026 – complete Practice Test
with Verified Answers
SECTION 1: ECG FUNDAMENTALS & CONDUCTION SYSTEM
(Questions 1-25)
Multiple Choice Questions
1. What does the horizontal axis on an ECG measure?
A) Voltage
B) Time
C) Amplitude
D) Resistance
Answer: B) Time
Rationale: The horizontal axis on ECG paper measures time. This allows clinicians to assess
the duration of various cardiac intervals such as the PR interval, QRS duration, and QT
interval. The standard paper speed is 25 mm/sec .
,2. How many seconds does one large box represent on standard ECG paper?
A) 0.04 seconds
B) 0.20 seconds
C) 0.10 seconds
D) 1.00 seconds
Answer: B) 0.20 seconds
Rationale: One large box equals five small boxes. Each small box represents 0.04 seconds,
so five small boxes = 0.20 seconds. This is essential for calculating heart rate and
measuring intervals .
3. What is the duration of one small box on standard ECG paper?
A) 0.04 seconds
B) 0.20 seconds
C) 0.10 seconds
D) 0.01 seconds
Answer: A) 0.04 seconds
Rationale: Each small box on the horizontal axis represents 0.04 seconds at the standard
paper speed of 25 mm/sec. This allows measurement of fine waveform details .
4. What voltage does one small box on the vertical axis represent?
,A) 0.1 mV
B) 0.5 mV
C) 1.0 mV
D) 0.01 mV
Answer: A) 0.1 mV
Rationale: Vertically, each small box represents 0.1 millivolts of amplitude. This helps
quantify the height of waveforms such as the R wave and T wave .
5. What is the standard paper speed for an ECG?
A) 10 mm/sec
B) 25 mm/sec
C) 50 mm/sec
D) 100 mm/sec
Answer: B) 25 mm/sec
Rationale: The standard recording speed for an ECG is 25 mm per second. This
standardization allows consistent interpretation of waveform durations and intervals
across different clinical settings .
6. Where is the SA node located?
A) Left atrium
B) Right atrium
, C) Left ventricle
D) Interventricular septum
Answer: B) Right atrium
Rationale: The sinoatrial (SA) node is located in the upper wall of the right atrium, near
the opening of the superior vena cava. It is the primary pacemaker of the heart, initiating
each cardiac cycle .
7. Where is the AV node located?
A) Floor of the right atrium
B) Apex of the right ventricle
C) Interventricular septum
D) Left atrium
Answer: A) Floor of the right atrium
Rationale: The atrioventricular (AV) node is located in the floor of the right atrium near
the interatrial septum. It serves as the electrical gateway between the atria and ventricles,
providing a brief delay to allow ventricular filling .
8. What structure directly follows the AV node in the conduction pathway?
A) Bundle branches
B) Purkinje fibers
C) Bundle of His
D) Internodal pathways
2025/2026 – complete Practice Test
with Verified Answers
SECTION 1: ECG FUNDAMENTALS & CONDUCTION SYSTEM
(Questions 1-25)
Multiple Choice Questions
1. What does the horizontal axis on an ECG measure?
A) Voltage
B) Time
C) Amplitude
D) Resistance
Answer: B) Time
Rationale: The horizontal axis on ECG paper measures time. This allows clinicians to assess
the duration of various cardiac intervals such as the PR interval, QRS duration, and QT
interval. The standard paper speed is 25 mm/sec .
,2. How many seconds does one large box represent on standard ECG paper?
A) 0.04 seconds
B) 0.20 seconds
C) 0.10 seconds
D) 1.00 seconds
Answer: B) 0.20 seconds
Rationale: One large box equals five small boxes. Each small box represents 0.04 seconds,
so five small boxes = 0.20 seconds. This is essential for calculating heart rate and
measuring intervals .
3. What is the duration of one small box on standard ECG paper?
A) 0.04 seconds
B) 0.20 seconds
C) 0.10 seconds
D) 0.01 seconds
Answer: A) 0.04 seconds
Rationale: Each small box on the horizontal axis represents 0.04 seconds at the standard
paper speed of 25 mm/sec. This allows measurement of fine waveform details .
4. What voltage does one small box on the vertical axis represent?
,A) 0.1 mV
B) 0.5 mV
C) 1.0 mV
D) 0.01 mV
Answer: A) 0.1 mV
Rationale: Vertically, each small box represents 0.1 millivolts of amplitude. This helps
quantify the height of waveforms such as the R wave and T wave .
5. What is the standard paper speed for an ECG?
A) 10 mm/sec
B) 25 mm/sec
C) 50 mm/sec
D) 100 mm/sec
Answer: B) 25 mm/sec
Rationale: The standard recording speed for an ECG is 25 mm per second. This
standardization allows consistent interpretation of waveform durations and intervals
across different clinical settings .
6. Where is the SA node located?
A) Left atrium
B) Right atrium
, C) Left ventricle
D) Interventricular septum
Answer: B) Right atrium
Rationale: The sinoatrial (SA) node is located in the upper wall of the right atrium, near
the opening of the superior vena cava. It is the primary pacemaker of the heart, initiating
each cardiac cycle .
7. Where is the AV node located?
A) Floor of the right atrium
B) Apex of the right ventricle
C) Interventricular septum
D) Left atrium
Answer: A) Floor of the right atrium
Rationale: The atrioventricular (AV) node is located in the floor of the right atrium near
the interatrial septum. It serves as the electrical gateway between the atria and ventricles,
providing a brief delay to allow ventricular filling .
8. What structure directly follows the AV node in the conduction pathway?
A) Bundle branches
B) Purkinje fibers
C) Bundle of His
D) Internodal pathways
