ECG ECG Interpretation

Question 1

What does the P wave on an ECG represent?

Accepted Answer

Atrial depolarization

Answer

The P wave represents the electrical depolarization spreading through the atria, triggering atrial contraction.

Question 2

A normal PR interval ranges from:

Accepted Answer

0.12 to 0.20 seconds

Answer

The normal PR interval is 0.12-0.20 seconds (3-5 small boxes), representing the time from atrial depolarization to ventricular depolarization.

Question 3

ST segment elevation most commonly indicates:

Accepted Answer

Acute myocardial injury

Answer

ST elevation is a hallmark finding of acute myocardial infarction (heart attack), indicating acute injury to the heart muscle.

Question 4

What does the QRS complex represent?

Accepted Answer

Ventricular depolarization

Answer

The QRS complex represents the rapid depolarization of both ventricles, triggering ventricular contraction and ejection of blood.

Question 5

What is the standard paper speed for ECG recording?

Accepted Answer

25 mm/sec

Answer

Standard ECG paper speed is 25 mm/second, where each small box represents 0.04 seconds and each large box represents 0.20 seconds.

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