CRAT ECG Waveform Measurements and Intervals 2

Question 1

The ST segment on the ECG represents:

Accepted Answer

The period between ventricular depolarization and repolarization

Answer

The ST segment represents the early phase of ventricular repolarization and is evaluated for elevation or depression suggesting ischemia or injury.

Question 2

Which calculation method uses the number of large squares between two R waves to estimate heart rate?

Accepted Answer

300 divided by number of large squares

Answer

The '300 rule' divides 300 by the number of large squares between two consecutive R waves to estimate heart rate quickly.

Question 3

What does a delta wave at the onset of the QRS complex suggest?

Accepted Answer

Pre-excitation syndrome (e.g., WPW)

Answer

A delta wave — a slurred upstroke at the start of the QRS — indicates pre-excitation of the ventricles via an accessory pathway, as seen in Wolff-Parkinson-White syndrome.

Question 4

An isoelectric baseline on the ECG refers to:

Accepted Answer

The normal baseline between waveforms with no electrical activity

Answer

The isoelectric line is the flat baseline between ECG waveforms, representing zero electrical potential and used as the reference point for ST segment analysis.

Question 5

The normal amplitude (height) of the R wave in lead II is typically:

Accepted Answer

5–25 mm

Answer

In most leads, a normal R wave measures 5–25 mm; excessively tall R waves may indicate ventricular hypertrophy.

CRAT - Certified Rhythm Analysis Technician Practice Test

CRAT - Certified Rhythm Analysis Technician Practice Test

CRAT ECG Waveform Measurements and Intervals 2