ECG's

Question 1

P wave

Answer 1

The P wave is produced by the depolarization of the atria. It indicates SA node function; and is best seen on leads LII and V1 (normally is upright/positive deflection)

Question 2

P-R interval

Answer 2

It is measured from the onset of the P wave to the beginning of the QRS complex.
Normal: 0.12-0.20 sec

Question 3

Q wave

Answer 3

The first negative deflection (downward) following the P wave and the P-R interval. It is due to septal depolarization

Question 4

R wave

Answer 4

The first positive deflection (upright). It follows the Q wave if present. It represents the depolarization of the left ventricle

Question 5

S wave

Answer 5

The first negative deflection after the R wave; and is usually the last portion of the QRS complex and final depolarization of the ventricles

Question 6

QRS interval

Answer 6

From the beginning of the Q wave to the end of the S wave; it represents the time in which ventricular depolarization occurs.
Normal: 0.04-0.10 sec

Question 7

S-T interval

Answer 7

Measured from the end of the S wave to the end of the T wave; represents repolarization of the ventricles

Question 8

T wave

Answer 8

Follows the S wave if present and ST segment; represents repolarization of the ventricles

Question 9

P-R segment

Answer 9

Measured from the end of the P wave to the beginning of QRS complex; normally isoelectric

Question 10

S-T segment

Answer 10

Measured form the end of the S wave to the beginning of the T wave; normally isoelectric

Question 11

QT interval

Answer 11

Measured form beginning of QRS complex to the end of the T wave