CRAT ECG Waveform Measurements and Intervals

Question 1

What is the normal duration of the PR interval on a standard ECG?

Accepted Answer

0.12–0.20 seconds

Answer

0.06–0.10 seconds

Answer

0.22–0.30 seconds

Answer

0.30–0.40 seconds

Question 2

On standard ECG paper, one large square represents how many seconds?

Accepted Answer

0.20 seconds

Answer

0.04 seconds

Answer

0.10 seconds

Answer

0.40 seconds

Question 3

A QRS complex measuring 0.14 seconds is considered:

Accepted Answer

Wide or abnormal

Answer

Normal

Answer

Slightly prolonged

Answer

Absent

Question 4

The QT interval is measured from:

Accepted Answer

Start of Q wave to end of T wave

Answer

Start of P wave to end of T wave

Answer

Start of QRS to peak of T wave

Answer

End of QRS to start of T wave

Question 5

Which waveform on the ECG represents ventricular repolarization?

Accepted Answer

T wave

Answer

P wave

Answer

QRS complex

Answer

U wave

Question 6

A corrected QT (QTc) interval greater than 500 ms is clinically significant because it:

Accepted Answer

Increases the risk of Torsades de Pointes

Answer

Indicates a first-degree AV block

Answer

Signals atrial fibrillation

Answer

Indicates a normal variant