PREP 2025 QUESTIONS AND ANSWERS
How long is a small box on an ECG rhythm strip? - ANS 0.04 seconds
How long is a big box (5 small boxes) on an ECG rhythm strip? - ANS 0.2 seconds
How many boxes on an ECG rhythm strip is = to 1 second? - ANS 5 big boxes
How do you determine heart rate using the 6 second method? - ANS Count the number of
QRS complexes within a 6 second strip and multiply by 10
How do you determine heart rate using the big block method? - ANS 300 divided by the
number of big blocks between 2 R waves
What does the P wave represent? - ANS atrial depolarization
What does the PR segment represent? - ANS the time required for the impulse to travel
through the AV node, where it is delayed, and through the bundle of His, bundle branches, and
Purkinje fibers, just before ventricular depolarization.
What does the QRS complex represent? - ANS ventricular depolarization
Where is the QRS interval measured? - ANS From the beginning of the Q (or R) wave to the
end of the S wave.
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, What does the T wave represent? - ANS ventricular repolarization
What does a U wave indicate? - ANS Possible hypokalemia
What does the QT interval represent? - ANS the total time required for ventricular
depolarization and repolarization
How is the QT interval measured? - ANS beginning of the QRS complex to end of the T wave
What rhythm is this? - ANS normal sinus rhythm
How long should the PR interval be? - ANS 3-5 small boxes (.12-.20 seconds)
How is the PR interval measured? - ANS From the beginning of P to the beginning of QRS.
How long should QRS complex be? - ANS less than 0.12 seconds (3 little boxes)
How is the ST segment measured? - ANS From the end of the QRS complex to the beginning
of the T wave
What does ST segment elevation indicate? - ANS myocardial infarction
What does ST segment depression indicate? - ANS myocardial ischemia
How long should the QT interval be? - ANS less than half of the R-R interval
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