ECG Basic Electrocardiogram 2 — Questions and Answers
Question 1: What does the P wave on an ECG tracing represent?
- Atrial depolarization (Correct answer)
- Ventricular depolarization
- Ventricular repolarization
- Atrial repolarization
Correct answer: Atrial depolarization
The P wave reflects the electrical impulse spreading through the atria, causing atrial depolarization.
Question 2: The QRS complex primarily represents which cardiac event?
- Ventricular depolarization (Correct answer)
- Atrial depolarization
- Atrial repolarization
- SA node firing
Correct answer: Ventricular depolarization
The QRS complex records the rapid depolarization of the right and left ventricles.
Question 3: What structure is normally the heart's primary pacemaker?
- Sinoatrial (SA) node (Correct answer)
- Atrioventricular (AV) node
- Bundle of His
- Purkinje fibers
Correct answer: Sinoatrial (SA) node
The SA node in the right atrium initiates the normal heartbeat and sets the heart rate.
Question 4: The T wave on a standard ECG represents:
- Ventricular repolarization (Correct answer)
- Atrial depolarization
- Ventricular depolarization
- AV node delay
Correct answer: Ventricular repolarization
The T wave reflects the recovery, or repolarization, of the ventricles.
Question 5: How many electrodes are placed on the chest in a standard 12-lead ECG?
- Six (Correct answer)
- Four
- Ten
- Twelve
Correct answer: Six
Six precordial (chest) electrodes are placed, V1 through V6, along with four limb electrodes.
Question 6: The PR interval on an ECG mainly reflects:
- Conduction delay through the AV node (Correct answer)
- Ventricular contraction time
- The speed of atrial repolarization
- Purkinje fiber recovery
Correct answer: Conduction delay through the AV node
The PR interval represents the time for the impulse to travel from the atria through the AV node to the ventricles.
Question 7: A normal adult resting heart rate typically falls within which range?
- 60 to 100 beats per minute (Correct answer)
- 100 to 140 beats per minute
- 30 to 50 beats per minute
- 120 to 160 beats per minute
Correct answer: 60 to 100 beats per minute
A normal resting sinus rhythm in adults is generally 60 to 100 beats per minute.
ECG Basic Electrocardiogram 2
What does the P wave on an ECG tracing represent?