2026 | Complete Study Guide with Verified
Questions & Detailed Rationales on ECG
Interpretation, Cardiac Anatomy,
Dysrhythmias & Lead Placement Techniques
• This practice exam contains 200 carefully crafted multiple-choice questions
designed to simulate the real EKG Technician Certification Exam — use it by
working through each question independently before checking the highlighted
correct answer and EXPERT RATIONALE below it.
• Each question features 5 options (A–E), a bolded correct answer, and a detailed
EXPERT RATIONALE — making this a complete self-study tool for mastering ECG
interpretation, cardiac anatomy, dysrhythmias, lead placement, and patient care.
SECTION 1: CARDIAC ANATOMY & PHYSIOLOGY
1. What is the primary pacemaker of the heart?
A) Atrioventricular (AV) node
B) Bundle of His
C) Purkinje fibers
D) Bundle branches
E) Sinoatrial (SA) node
Correct Answer: E) Sinoatrial (SA) node
EXPERT RATIONALE: The SA node is located in the right atrium and normally fires
at 60–100 beats per minute, making it the heart's primary pacemaker. It initiates
each electrical impulse that triggers a normal heartbeat.
2. Which chamber of the heart receives oxygenated blood from the lungs?
A) Right atrium
,B) Right ventricle
C) Left ventricle
D) Left atrium
E) Interventricular septum
Correct Answer: D) Left atrium
EXPERT RATIONALE: Oxygenated blood returns from the lungs via the pulmonary
veins and enters the left atrium first before moving to the left ventricle for systemic
circulation.
3. The AV node's intrinsic firing rate is:
A) 60–100 bpm
B) 100–150 bpm
C) 40–60 bpm
D) 20–40 bpm
E) 80–100 bpm
Correct Answer: C) 40–60 bpm
EXPERT RATIONALE: The AV node serves as a secondary pacemaker with an
intrinsic rate of 40–60 bpm. It takes over pacing if the SA node fails.
4. Which valve separates the left atrium from the left ventricle?
A) Tricuspid valve
B) Aortic valve
C) Pulmonic valve
D) Mitral valve
E) Eustachian valve
, Correct Answer: D) Mitral valve
EXPERT RATIONALE: The mitral (bicuspid) valve is located between the left atrium
and left ventricle. It prevents backflow of blood during ventricular contraction.
5. The Purkinje fibers have an intrinsic pacing rate of:
A) 60–100 bpm
B) 40–60 bpm
C) 20–40 bpm
D) 100–120 bpm
E) 50–70 bpm
Correct Answer: C) 20–40 bpm
EXPERT RATIONALE: Purkinje fibers are the slowest pacemaker cells, firing at 20–
40 bpm. They act as the last resort pacemaker if both the SA and AV nodes fail.
6. Which coronary artery supplies the SA node in most individuals?
A) Left anterior descending artery
B) Left circumflex artery
C) Left main coronary artery
D) Right coronary artery
E) Posterior descending artery
Correct Answer: D) Right coronary artery
EXPERT RATIONALE: In approximately 60% of individuals, the SA node is supplied
by the right coronary artery, which is why right coronary occlusion can lead to
bradyarrhythmias.
, 7. Depolarization of the ventricles is represented on the ECG by the:
A) P wave
B) T wave
C) U wave
D) QRS complex
E) PR interval
Correct Answer: D) QRS complex
EXPERT RATIONALE: The QRS complex represents ventricular depolarization — the
electrical event that triggers ventricular contraction (systole).
8. Which layer of the heart is responsible for its pumping action?
A) Epicardium
B) Pericardium
C) Endocardium
D) Myocardium
E) Visceral pericardium
Correct Answer: D) Myocardium
EXPERT RATIONALE: The myocardium is the muscular middle layer of the heart
wall. Its coordinated contraction is responsible for pumping blood throughout the
body.
9. The right ventricle pumps blood to the:
A) Aorta
B) Left atrium
C) Systemic circulation