BAYCARE EKG COMPETENCY EXAM PRACTICE
QUESTIONS WITH VERIFIED ANSWERS AND
DETAILED RATIONALES
1. A patient has a heart rate of 42 bpm, no visible P waves, and a wide QRS (0.14
sec). What is the rhythm?
A) Junctional escape rhythm
B) Atrial fibrillation with slow ventricular response
C) Idioventricular rhythm
D) First-degree AV block
Correct Answer: C
*Rationale: Idioventricular rhythm occurs when the ventricles act as the
pacemaker (rate 20–40 bpm, wide QRS >0.12 sec, absent P waves). Junctional
escape rhythm (A) is narrow QRS (40–60 bpm). Atrial fibrillation (B) has irregularly
irregular narrow QRS unless aberrancy. First-degree AV block (D) has normal QRS
and prolonged PR.*
2. Which lead is most sensitive for inferior wall myocardial ischemia?
A) V2
B) aVL
C) II, III, aVF
D) V5
Correct Answer: C
*Rationale: Leads II, III, and aVF directly view the inferior wall of the left ventricle
(supplied by the RCA). V2 (A) is septal/anterior; aVL (B) is high lateral; V5 (D) is
lateral.*
,3. A 68-year-old has a regular rhythm at 88 bpm, PR 0.20 sec, QRS 0.10 sec. Every
other QRS is preceded by an abnormal P wave with different morphology. What is
the diagnosis?
A) Atrial bigeminy
B) Wandering atrial pacemaker
C) Second-degree AV block type I
D) Premature ventricular complexes (PVCs) in bigeminy
Correct Answer: A
Rationale: Atrial bigeminy = normal beat followed by a premature atrial complex
(PAC) with an abnormal P wave, then a pause. Wandering pacemaker (B) has at
least three different P-wave morphologies. AV block (C) affects PR interval. PVCs
(D) have wide QRS, not abnormal P waves.
4. Which of the following best describes ST-segment elevation in pericarditis?
A) Localized to leads V1–V4 only
B) Diffuse, concave upward, with PR depression
C) Deep symmetric T-wave inversions only
D) ST elevation that mirrors in inferior leads
Correct Answer: B
Rationale: Acute pericarditis causes diffuse ST elevation (concave up) and PR
segment depression (due to atrial inflammation). Option A suggests anterior MI. C
is seen in Wellens’ syndrome. D suggests reciprocal changes in MI.
5. What is the QT interval if the patient’s heart rate is 60 bpm and QT measured =
0.44 sec?
A) Normal
B) Prolonged
C) Short
D) Indeterminate
,Correct Answer: A
Rationale: At 60 bpm, the upper normal limit for QTc is ~0.44 sec for men and 0.46
sec for women. Since the measured QT is 0.44 sec and rate is 60 bpm, it is normal
(QTc ~0.44 sec using Bazett).
6. Which lead is used to identify P-wave morphology for suspected right atrial
enlargement?
A) Lead I
B) Lead II
C) Lead V1
D) Lead aVR
Correct Answer: C
Rationale: Right atrial enlargement → tall, peaked P wave >2.5 mm in leads II, III,
aVF, but best seen in V1 as a prominent positive initial component (P wave >1.5
mm). Lead II (B) is also used but V1 is key for distinguishing biatrial vs right atrial.
7. A patient with palpitations has an ECG with a narrow QRS, rate 190 bpm,
regular, and no visible P waves. What is most likely?
A) Atrial flutter with 2:1 block
B) Sinus tachycardia
C) AV nodal reentrant tachycardia (AVNRT)
D) Ventricular tachycardia
Correct Answer: C
Rationale: AVNRT is a regular narrow-complex tachycardia often without visible P
waves (P waves hidden in QRS). Atrial flutter (A) often has sawtooth waves; sinus
tachycardia (B) has clear P waves; VT (D) is wide QRS.
8. What is the most likely rhythm if P waves are absent, the ventricular rate is 110
bpm, irregularly irregular, and QRS narrow?
, A) Atrial flutter
B) Multifocal atrial tachycardia
C) Atrial fibrillation
D) Sinus arrhythmia
Correct Answer: C
Rationale: Atrial fibrillation has no P waves, irregularly irregular rhythm, narrow
QRS unless aberrancy. Atrial flutter (A) has regular or regularly irregular sawtooth.
MAT (B) has at least three distinct P-wave morphologies. Sinus arrhythmia (D) has
P waves with normal morphology.
9. In a 12-lead ECG, which leads are contiguous for anteroseptal wall?
A) V1, V2
B) V3, V4
C) II, III, aVF
D) V5, V6, I, aVL
Correct Answer: A
*Rationale: Anteroseptal leads = V1, V2 (sometimes V3). V3–V4 are anterior.
II/III/aVF = inferior. V5–V6/I/aVL = lateral.*
10. Which interval is measured from the start of the QRS to the end of the T
wave?
A) PR interval
B) QT interval
C) QRS duration
D) PP interval
Correct Answer: B
Rationale: The QT interval represents total ventricular depolarization and
repolarization. PR interval (A) = P to QRS. QRS duration (C) = depolarization only.
PP interval (D) = atrial cycle length.
QUESTIONS WITH VERIFIED ANSWERS AND
DETAILED RATIONALES
1. A patient has a heart rate of 42 bpm, no visible P waves, and a wide QRS (0.14
sec). What is the rhythm?
A) Junctional escape rhythm
B) Atrial fibrillation with slow ventricular response
C) Idioventricular rhythm
D) First-degree AV block
Correct Answer: C
*Rationale: Idioventricular rhythm occurs when the ventricles act as the
pacemaker (rate 20–40 bpm, wide QRS >0.12 sec, absent P waves). Junctional
escape rhythm (A) is narrow QRS (40–60 bpm). Atrial fibrillation (B) has irregularly
irregular narrow QRS unless aberrancy. First-degree AV block (D) has normal QRS
and prolonged PR.*
2. Which lead is most sensitive for inferior wall myocardial ischemia?
A) V2
B) aVL
C) II, III, aVF
D) V5
Correct Answer: C
*Rationale: Leads II, III, and aVF directly view the inferior wall of the left ventricle
(supplied by the RCA). V2 (A) is septal/anterior; aVL (B) is high lateral; V5 (D) is
lateral.*
,3. A 68-year-old has a regular rhythm at 88 bpm, PR 0.20 sec, QRS 0.10 sec. Every
other QRS is preceded by an abnormal P wave with different morphology. What is
the diagnosis?
A) Atrial bigeminy
B) Wandering atrial pacemaker
C) Second-degree AV block type I
D) Premature ventricular complexes (PVCs) in bigeminy
Correct Answer: A
Rationale: Atrial bigeminy = normal beat followed by a premature atrial complex
(PAC) with an abnormal P wave, then a pause. Wandering pacemaker (B) has at
least three different P-wave morphologies. AV block (C) affects PR interval. PVCs
(D) have wide QRS, not abnormal P waves.
4. Which of the following best describes ST-segment elevation in pericarditis?
A) Localized to leads V1–V4 only
B) Diffuse, concave upward, with PR depression
C) Deep symmetric T-wave inversions only
D) ST elevation that mirrors in inferior leads
Correct Answer: B
Rationale: Acute pericarditis causes diffuse ST elevation (concave up) and PR
segment depression (due to atrial inflammation). Option A suggests anterior MI. C
is seen in Wellens’ syndrome. D suggests reciprocal changes in MI.
5. What is the QT interval if the patient’s heart rate is 60 bpm and QT measured =
0.44 sec?
A) Normal
B) Prolonged
C) Short
D) Indeterminate
,Correct Answer: A
Rationale: At 60 bpm, the upper normal limit for QTc is ~0.44 sec for men and 0.46
sec for women. Since the measured QT is 0.44 sec and rate is 60 bpm, it is normal
(QTc ~0.44 sec using Bazett).
6. Which lead is used to identify P-wave morphology for suspected right atrial
enlargement?
A) Lead I
B) Lead II
C) Lead V1
D) Lead aVR
Correct Answer: C
Rationale: Right atrial enlargement → tall, peaked P wave >2.5 mm in leads II, III,
aVF, but best seen in V1 as a prominent positive initial component (P wave >1.5
mm). Lead II (B) is also used but V1 is key for distinguishing biatrial vs right atrial.
7. A patient with palpitations has an ECG with a narrow QRS, rate 190 bpm,
regular, and no visible P waves. What is most likely?
A) Atrial flutter with 2:1 block
B) Sinus tachycardia
C) AV nodal reentrant tachycardia (AVNRT)
D) Ventricular tachycardia
Correct Answer: C
Rationale: AVNRT is a regular narrow-complex tachycardia often without visible P
waves (P waves hidden in QRS). Atrial flutter (A) often has sawtooth waves; sinus
tachycardia (B) has clear P waves; VT (D) is wide QRS.
8. What is the most likely rhythm if P waves are absent, the ventricular rate is 110
bpm, irregularly irregular, and QRS narrow?
, A) Atrial flutter
B) Multifocal atrial tachycardia
C) Atrial fibrillation
D) Sinus arrhythmia
Correct Answer: C
Rationale: Atrial fibrillation has no P waves, irregularly irregular rhythm, narrow
QRS unless aberrancy. Atrial flutter (A) has regular or regularly irregular sawtooth.
MAT (B) has at least three distinct P-wave morphologies. Sinus arrhythmia (D) has
P waves with normal morphology.
9. In a 12-lead ECG, which leads are contiguous for anteroseptal wall?
A) V1, V2
B) V3, V4
C) II, III, aVF
D) V5, V6, I, aVL
Correct Answer: A
*Rationale: Anteroseptal leads = V1, V2 (sometimes V3). V3–V4 are anterior.
II/III/aVF = inferior. V5–V6/I/aVL = lateral.*
10. Which interval is measured from the start of the QRS to the end of the T
wave?
A) PR interval
B) QT interval
C) QRS duration
D) PP interval
Correct Answer: B
Rationale: The QT interval represents total ventricular depolarization and
repolarization. PR interval (A) = P to QRS. QRS duration (C) = depolarization only.
PP interval (D) = atrial cycle length.
