300 REAL EXAM QUESTIONS AND CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED A+
Question 1
What does the P wave on an electrocardiogram (ECG) represent?
A) Ventricular depolarization
B) Atrial repolarization
C) Atrial depolarization
D) Ventricular repolarization
E) The absolute refractory period
Correct Answer: C) Atrial depolarization
Rationale: The P wave signifies the electrical impulse originating in
the sinoatrial (SA) node and spreading through the atria, causing
them to contract (depolarize).
Question 2
A patient presents with a regular rhythm, a heart rate of 110/min, P waves
before every QRS complex, and a normal PR interval. Which rhythm is this?
A) Sinus bradycardia
B) Sinus tachycardia
C) Atrial fibrillation
D) Junctional rhythm
E) Ventricular tachycardia
Correct Answer: B) Sinus tachycardia
Rationale: Sinus tachycardia is characterized by a regular rhythm, P
waves preceding each QRS, a normal PR interval, and a heart rate
between 100-160 beats/min.
Question 3
Which of the following leads is considered the ground electrode in a 12-lead
ECG?
A) Right arm (RA)
B) Left arm (LA)
C) Right leg (RL)
D) Left leg (LL)
E) V1
Correct Answer: C) Right leg (RL)
Rationale: The right leg (RL) electrode serves as the ground
electrode in a 12-lead ECG, minimizing electrical interference.
Question 4
When placing electrodes for a 12-lead ECG, where should the V4 electrode
,be positioned?
A) Fourth intercostal space, right sternal border
B) Fifth intercostal space, midclavicular line
C) Fourth intercostal space, left sternal border
D) Between V2 and V4
E) Fifth intercostal space, anterior axillary line
Correct Answer: B) Fifth intercostal space, midclavicular line
Rationale: The V4 electrode is placed in the fifth intercostal space at
the midclavicular line.
Question 5
What artifact appears as a series of small, irregular spikes on the ECG tracing
and is often caused by muscle tremors or patient movement?
A) Somatic tremor
B) Wandering baseline
C) AC interference
D) Interrupted baseline
E) Baseline drift
Correct Answer: A) Somatic tremor
Rationale: Somatic tremor, or muscle artifact, manifests as uneven
spikes due to voluntary or involuntary muscle contractions.
Question 6
Which cardiac rhythm is characterized by a "sawtooth" appearance of the P
waves (F waves) and an atrial rate typically between 250-350 beats/min?
A) Atrial fibrillation
B) Atrial flutter
C) Ventricular fibrillation
D) Supraventricular tachycardia
E) Premature atrial contractions
Correct Answer: B) Atrial flutter
Rationale: Atrial flutter is identified by distinct "sawtooth" F waves
and a rapid, regular atrial rate, commonly around 250-350
beats/min.
Question 7
Before performing an ECG, what should the EKG technician always do first to
ensure patient safety and privacy?
A) Explain the procedure in detail.
B) Gather all necessary equipment.
C) Obtain informed consent.
, D) Verify patient identity.
E) Provide a gown and drape.
Correct Answer: D) Verify patient identity.
Rationale: Verifying patient identity using at least two identifiers is
the most critical first step to ensure the correct patient receives the
procedure and to maintain patient safety.
Question 8
What is the normal duration for the PR interval on an adult ECG?
A) 0.04-0.10 seconds
B) 0.12-0.20 seconds
C) 0.20-0.30 seconds
D) 0.08-0.12 seconds
E) 0.20-0.24 seconds
Correct Answer: B) 0.12-0.20 seconds
Rationale: A normal PR interval, representing atrial depolarization
and AV nodal delay, typically ranges from 0.12 to 0.20 seconds (3 to
5 small squares) in adults.
Question 9
In a 5-lead ECG for continuous monitoring, where is the green electrode
typically placed?
A) Left upper chest, below the clavicle
B) Right upper chest, below the clavicle
C) Left lower abdominal area, near the waistline
D) Right lower abdominal area, near the waistline
E) Center of the chest
Correct Answer: D) Right lower abdominal area, near the waistline
Rationale: In a 5-lead configuration, the green electrode is typically
placed on the right lower quadrant of the abdomen or right lower
chest to serve as the ground.
Question 10
A patient complains of dizziness and shortness of breath. The ECG shows a
heart rate of 35/min, regular rhythm, P waves present before QRS but no
clear relationship, and prolonged PR intervals. This could indicate:
A) Second-degree AV block, Type I (Wenckebach)
B) Second-degree AV block, Type II
C) Third-degree (complete) AV block
D) Sinus arrhythmia
E) First-degree AV block