|Questions with Detailed Rationales, Rhythm
Interpretation, Cardiac Arrhythmias, MI Localization &
NCLEX/EKG Review Guide 2026
This BayCare EKG Practice Test is designed to simulate real clinical and certification-style
ECG interpretation questions commonly seen in, NCLEX, and hospital competency exams. It
focuses on:
Cardiac rhythm recognition
Acute ECG interpretation
Myocardial infarction localization
AV blocks and dysrhythmias
Electrolyte-related ECG changes
Emergency management priorities
1.
A 62-year-old patient presents with dizziness and palpitations. The ECG shows a regular
rhythm at 170 bpm. The QRS complexes are narrow, and P waves are not clearly visible.
What is the most likely rhythm?
A. Sinus tachycardia
B. Atrial fibrillation
C. Supraventricular tachycardia (SVT)
D. Ventricular tachycardia
Answer: C
**Explanation:
SVT is characterized by a sudden onset of rapid, regular rhythm (150–250 bpm) with
narrow QRS complexes. P waves are often hidden within the QRS or T wave due to the
fast rate.
2.
,A patient’s ECG shows an “irregularly irregular” rhythm. There are no identifiable P waves
and the ventricular rate varies between 90–150 bpm.
What rhythm is this?
A. Atrial flutter
B. Atrial fibrillation
C. Ventricular fibrillation
D. Sinus arrhythmia
Answer: B
**Explanation:
Atrial fibrillation is defined by no organized atrial activity (no P waves) and an irregularly
irregular ventricular rhythm due to chaotic atrial impulses.
3.
An ECG shows ST-segment elevation in leads II, III, and aVF.
Which coronary artery is most likely involved?
A. Left anterior descending (LAD)
B. Right coronary artery (RCA)
C. Left circumflex artery
D. Left main coronary artery
Answer: B
**Explanation:
Leads II, III, and aVF represent the inferior wall of the heart, most commonly supplied by
the right coronary artery (RCA).
4.
A 70-year-old patient has chest pain. ECG shows ST elevation in V1–V4.
What area of the heart is affected?
A. Inferior wall
B. Lateral wall
, C. Anterior wall
D. Posterior wall
Answer: C
**Explanation:
Leads V1–V4 represent the anterior wall, typically supplied by the left anterior
descending (LAD) artery.
5.
A patient’s ECG shows a wide-complex tachycardia at 160 bpm with no discernible P
waves.
What is the priority interpretation?
A. SVT
B. Ventricular tachycardia
C. Atrial flutter
D. First-degree AV block
Answer: B
**Explanation:
A wide QRS tachycardia (>0.12 sec) should be treated as ventricular tachycardia until
proven otherwise, a potentially life-threatening rhythm.
6.
The ECG shows a PR interval consistently greater than 0.20 seconds with every P wave
followed by a QRS.
What is the diagnosis?
A. First-degree AV block
B. Second-degree AV block type I