NHA EKG PRACTICE EXAM
1. Which electrode is used as the ground in a standard 12-lead
ECG?
A. RA
B. RL
C. LL
D. V1
Rationale: The right leg (RL) serves as the ground to reduce
electrical interference.
2. The PR interval represents:
A. Ventricular depolarization
B. Atrial depolarization and AV node delay
C. Atrial repolarization
D. Ventricular repolarization
Rationale: The PR interval reflects atrial depolarization plus
conduction through the AV node.
3. A widened QRS complex on an EKG suggests:
,A. Hypokalemia
B. Ventricular conduction delay
C. Normal conduction
D. Atrial flutter
Rationale: A wide QRS indicates delayed conduction through
ventricles, often from bundle branch block.
4. Lead II views the heart from which direction?
A. Right arm
B. Left arm
C. Left leg
D. Chest
Rationale: Lead II records electrical activity from RA to LL,
giving an inferior view.
5. V1 is placed at:
A. 4th ICS mid-clavicular
B. 4th ICS right sternal border
C. 5th ICS mid-clavicular
D. 2nd ICS left sternal
Rationale: V1 sits at the 4th intercostal space at the right
sternal border.
,6. Artifact caused by muscle tremors is called:
A. Wandering baseline
B. Somatic tremor
C. AC interference
D. Baseline shift
Rationale: Somatic tremor comes from voluntary or
involuntary muscle activity.
7. A patient with Parkinson’s most commonly shows which
artifact?
A. Wandering baseline
B. Somatic tremor
C. AC interference
D. Interrupted baseline
Rationale: Muscle rigidity and tremors cause somatic artifact.
8. A vertical line on the EKG tracing that is extremely tall and
narrow is:
A. Motion artifact
B. Wandering baseline
C. AC interference
D. Somatic tremor
, Rationale: AC interference appears as uniform spikes from
electrical sources.
9. The normal paper speed of an ECG is:
A. 10 mm/sec
B. 15 mm/sec
C. 25 mm/sec
D. 30 mm/sec
Rationale: Standard speed is 25 mm/sec for accurate
measurement.
10. How many seconds are represented by one large box?
A. 0.02
B. 0.1
C. 0.2
D. 0.5
Rationale: One large box is 0.2 seconds.
11. A normal QT interval is generally:
A. <0.20 seconds
B. <0.28 seconds
C. <0.44 seconds
1. Which electrode is used as the ground in a standard 12-lead
ECG?
A. RA
B. RL
C. LL
D. V1
Rationale: The right leg (RL) serves as the ground to reduce
electrical interference.
2. The PR interval represents:
A. Ventricular depolarization
B. Atrial depolarization and AV node delay
C. Atrial repolarization
D. Ventricular repolarization
Rationale: The PR interval reflects atrial depolarization plus
conduction through the AV node.
3. A widened QRS complex on an EKG suggests:
,A. Hypokalemia
B. Ventricular conduction delay
C. Normal conduction
D. Atrial flutter
Rationale: A wide QRS indicates delayed conduction through
ventricles, often from bundle branch block.
4. Lead II views the heart from which direction?
A. Right arm
B. Left arm
C. Left leg
D. Chest
Rationale: Lead II records electrical activity from RA to LL,
giving an inferior view.
5. V1 is placed at:
A. 4th ICS mid-clavicular
B. 4th ICS right sternal border
C. 5th ICS mid-clavicular
D. 2nd ICS left sternal
Rationale: V1 sits at the 4th intercostal space at the right
sternal border.
,6. Artifact caused by muscle tremors is called:
A. Wandering baseline
B. Somatic tremor
C. AC interference
D. Baseline shift
Rationale: Somatic tremor comes from voluntary or
involuntary muscle activity.
7. A patient with Parkinson’s most commonly shows which
artifact?
A. Wandering baseline
B. Somatic tremor
C. AC interference
D. Interrupted baseline
Rationale: Muscle rigidity and tremors cause somatic artifact.
8. A vertical line on the EKG tracing that is extremely tall and
narrow is:
A. Motion artifact
B. Wandering baseline
C. AC interference
D. Somatic tremor
, Rationale: AC interference appears as uniform spikes from
electrical sources.
9. The normal paper speed of an ECG is:
A. 10 mm/sec
B. 15 mm/sec
C. 25 mm/sec
D. 30 mm/sec
Rationale: Standard speed is 25 mm/sec for accurate
measurement.
10. How many seconds are represented by one large box?
A. 0.02
B. 0.1
C. 0.2
D. 0.5
Rationale: One large box is 0.2 seconds.
11. A normal QT interval is generally:
A. <0.20 seconds
B. <0.28 seconds
C. <0.44 seconds
