2026 APEX EKG TEST EXAM – QUESTIONS WITH
CORRECT ANSWERS & RATIONALES -Master ECG
Interpretation for Nursing & Cardiology Certification
Accelerate your cardiac rhythm recognition and pass your
certification with this definitive APEX EKG test preparation
guide packed with real questions, answers, and detailed
rationales. This comprehensive resource covers EKG grid
calculations, interval measurements, advanced cardiac
electrophysiology, and complex arrhythmia interpretation
(including heart blocks, AFib, and telemetry monitoring). It
is an essential study tool for nursing students and
telemetry professionals looking to secure a top grade and
clinical confidence
QUESTION 1
What is the most common cause of ST-segment elevation in
asymptomatic young adults?
A) Acute myocardial infarction
B) Early repolarization
C) Pericarditis
D) Hyperkalemia
Answer: B) Early repolarization
Rationale: Early repolarization is a benign ECG variant commonly seen in
young, healthy adults, particularly athletes. It presents as ST-segment
elevation with a concave upward morphology, often with prominent J waves.
Unlike STEMI, it does not have reciprocal ST depression or dynamic changes .
,QUESTION 2
What is the characteristic ECG finding in pericarditis?
A) Diffuse ST elevation with PR depression
B) ST elevation confined to leads V1-V4
C) ST depression in all leads
D) Peaked T waves
Answer: A) Diffuse ST elevation with PR depression
Rationale: Pericarditis presents with diffuse ST elevation (concave upward)
and PR depression across multiple leads. Unlike STEMI, the ST elevation is
widespread (not confined to one coronary territory) and there are no
reciprocal changes. PR depression is a distinguishing feature .
QUESTION 3
What is the most common cause of ST-segment depression on a
resting ECG?
A) Subendocardial ischemia
B) Left ventricular hypertrophy
C) Hyperkalemia
D) Pericarditis
Answer: B) Left ventricular hypertrophy
Rationale: Left ventricular hypertrophy (LVH) is a common cause of ST-
segment depression on resting ECG due to the "strain" pattern. This is
characterized by down-sloping ST depression with asymmetrical T wave
inversion in the lateral leads (V5-V6, I, aVL). Ischemia should be suspected
when there is ST depression with dynamic changes or in symptomatic
patients .
,QUESTION 4
What is the most common cause of a low-voltage ECG?
A) COPD
B) Pericardial effusion
C) Hyperkalemia
D) Myocardial infarction
Answer: B) Pericardial effusion
Rationale: Pericardial effusion is the most common cause of low-voltage
QRS complexes on ECG. The fluid surrounding the heart acts as an electrical
insulator, reducing the amplitude of QRS complexes. COPD can also cause
low voltage but is not as common a cause .
QUESTION 5
What is the ECG finding in cardiac tamponade?
A) ST elevation
B) Low voltage with electrical alternans
C) Peaked T waves
D) Delta waves
Answer: B) Low voltage with electrical alternans
Rationale: Cardiac tamponade is a medical emergency that presents with
low-voltage QRS complexes and electrical alternans (alternating QRS
amplitudes). Electrical alternans occurs due to the heart swinging within the
fluid-filled pericardial sac, causing a changing electrical axis. This is a classic
but not sensitive sign .
, QUESTION 6
What is the most common cause of electrical alternans?
A) Pericarditis
B) Cardiac tamponade
C) Myocardial infarction
D) Hyperkalemia
Answer: B) Cardiac tamponade
Rationale: Electrical alternans—alternating amplitude of QRS complexes—is
most commonly associated with cardiac tamponade. It can also be seen in
other conditions but is a classic finding of pericardial effusion with
hemodynamic compromise .
QUESTION 7
What is the ECG finding in hyperthyroidism?
A) Sinus bradycardia
B) Sinus tachycardia with high-voltage QRS
C) Peaked T waves
D) Prolonged QT interval
Answer: B) Sinus tachycardia with high-voltage QRS
Rationale: Hyperthyroidism causes sinus tachycardia and increased QRS
voltage due to increased metabolic demand. The heart rate is typically >100
bpm. Atrial fibrillation is more common in older patients .
QUESTION 8
What is the most common ECG finding in patients with
cerebrovascular accidents (CVA)?
CORRECT ANSWERS & RATIONALES -Master ECG
Interpretation for Nursing & Cardiology Certification
Accelerate your cardiac rhythm recognition and pass your
certification with this definitive APEX EKG test preparation
guide packed with real questions, answers, and detailed
rationales. This comprehensive resource covers EKG grid
calculations, interval measurements, advanced cardiac
electrophysiology, and complex arrhythmia interpretation
(including heart blocks, AFib, and telemetry monitoring). It
is an essential study tool for nursing students and
telemetry professionals looking to secure a top grade and
clinical confidence
QUESTION 1
What is the most common cause of ST-segment elevation in
asymptomatic young adults?
A) Acute myocardial infarction
B) Early repolarization
C) Pericarditis
D) Hyperkalemia
Answer: B) Early repolarization
Rationale: Early repolarization is a benign ECG variant commonly seen in
young, healthy adults, particularly athletes. It presents as ST-segment
elevation with a concave upward morphology, often with prominent J waves.
Unlike STEMI, it does not have reciprocal ST depression or dynamic changes .
,QUESTION 2
What is the characteristic ECG finding in pericarditis?
A) Diffuse ST elevation with PR depression
B) ST elevation confined to leads V1-V4
C) ST depression in all leads
D) Peaked T waves
Answer: A) Diffuse ST elevation with PR depression
Rationale: Pericarditis presents with diffuse ST elevation (concave upward)
and PR depression across multiple leads. Unlike STEMI, the ST elevation is
widespread (not confined to one coronary territory) and there are no
reciprocal changes. PR depression is a distinguishing feature .
QUESTION 3
What is the most common cause of ST-segment depression on a
resting ECG?
A) Subendocardial ischemia
B) Left ventricular hypertrophy
C) Hyperkalemia
D) Pericarditis
Answer: B) Left ventricular hypertrophy
Rationale: Left ventricular hypertrophy (LVH) is a common cause of ST-
segment depression on resting ECG due to the "strain" pattern. This is
characterized by down-sloping ST depression with asymmetrical T wave
inversion in the lateral leads (V5-V6, I, aVL). Ischemia should be suspected
when there is ST depression with dynamic changes or in symptomatic
patients .
,QUESTION 4
What is the most common cause of a low-voltage ECG?
A) COPD
B) Pericardial effusion
C) Hyperkalemia
D) Myocardial infarction
Answer: B) Pericardial effusion
Rationale: Pericardial effusion is the most common cause of low-voltage
QRS complexes on ECG. The fluid surrounding the heart acts as an electrical
insulator, reducing the amplitude of QRS complexes. COPD can also cause
low voltage but is not as common a cause .
QUESTION 5
What is the ECG finding in cardiac tamponade?
A) ST elevation
B) Low voltage with electrical alternans
C) Peaked T waves
D) Delta waves
Answer: B) Low voltage with electrical alternans
Rationale: Cardiac tamponade is a medical emergency that presents with
low-voltage QRS complexes and electrical alternans (alternating QRS
amplitudes). Electrical alternans occurs due to the heart swinging within the
fluid-filled pericardial sac, causing a changing electrical axis. This is a classic
but not sensitive sign .
, QUESTION 6
What is the most common cause of electrical alternans?
A) Pericarditis
B) Cardiac tamponade
C) Myocardial infarction
D) Hyperkalemia
Answer: B) Cardiac tamponade
Rationale: Electrical alternans—alternating amplitude of QRS complexes—is
most commonly associated with cardiac tamponade. It can also be seen in
other conditions but is a classic finding of pericardial effusion with
hemodynamic compromise .
QUESTION 7
What is the ECG finding in hyperthyroidism?
A) Sinus bradycardia
B) Sinus tachycardia with high-voltage QRS
C) Peaked T waves
D) Prolonged QT interval
Answer: B) Sinus tachycardia with high-voltage QRS
Rationale: Hyperthyroidism causes sinus tachycardia and increased QRS
voltage due to increased metabolic demand. The heart rate is typically >100
bpm. Atrial fibrillation is more common in older patients .
QUESTION 8
What is the most common ECG finding in patients with
cerebrovascular accidents (CVA)?
