AHN 568 COMPLETE REVIEW 2026
QUESTIONS WITH SOLUTIONS GRADED A+
◉Normal QRS. Answer: normal measurement/duration is less than
0.12 sec or 3 boxes. Consists of the Q wave, R wave, and S wave.
Represents ventricular depolarization (and contraction) and atrial
repolarization.
◉T wave. Answer: Normal measurement is less than 5 mm high.
Rounded, usually a low, broad hump.. Positive in lead II. Represents
the rapid phase of ventricular repolarization. After the QRS complex.
◉PR Interval. Answer: normal PRI is 0.12-0.2 seconds in adults.
Represents the start of atrial depolarization to the start of
ventricular depolarization. It constitutes the beginning of the P wave
and the brief delay, or pause, before depolarization is conducted to
the ventricles. This brief pause allows the blood from the atria to
pass through the AV valves into the ventricles. (Note, this slow
conduction through the AV node is carried by calcium (Ca++) ions
◉ST Segment. Answer: Normally at the isoelectric line on the EKG.
,A horizontal, flat, and normally at the baseline level after the QRS.
Elevation or depression of 1 mm (one box) or more is considered
abnormal.
◉QT interval. Answer: Measured from the beginning of the QRS until
the end of the T wave. Represents the start of ventricular
depolarization to the end of ventricular repolarization. QT intervals
vary with HR. Precise QT interval measurements are corrected for
rate, so they are called QTc values.
REMEMBER THIS: as a rule of thumb, the QT interval is considered
normal when it is less than half of the R-to-R interval at normal rates
◉U Waves. Answer: Waves that are present in between T & p Waves
predominate if > 1-2mm or 25% of the height of the T wave
delayed purkinjie fiber re-polarization
◉Rule of 300s. Answer: find an R wave that lands on a heave line.
That's your starting point.
Then assign 300, 150, 100, 75, 60, 50 to the following heavy lines.
Wherever the next R-wave falls gives you the approximate rate.
, ◉6 second strip method. Answer: Count QRS complexes on a 6-
second strip and multiply by 10. Least accurate, provides mean rate.
◉Small square on EKG. Answer: 0.04 sec
◉Large sqaure on EKG. Answer: 0.20 sec
◉Asystole. Answer: cardiac arrest with no discernable electrical
activity
- flatline EKG
- P waves and QRS complex not present
◉Supraventricular Tachycardia (SVT). Answer: § regular but fast
rhythm
§ rate 150-250
§ P wave merged with T wave
§ PRI variable & difficult to measure
§ QRSa typically narrow
§ Common causes: stimulants, electrolyte imbalance, hypoxia
◉Atrial Fibrillation (A-Fib). Answer: § irregular rhythm
§ absent P waves and PRI
QUESTIONS WITH SOLUTIONS GRADED A+
◉Normal QRS. Answer: normal measurement/duration is less than
0.12 sec or 3 boxes. Consists of the Q wave, R wave, and S wave.
Represents ventricular depolarization (and contraction) and atrial
repolarization.
◉T wave. Answer: Normal measurement is less than 5 mm high.
Rounded, usually a low, broad hump.. Positive in lead II. Represents
the rapid phase of ventricular repolarization. After the QRS complex.
◉PR Interval. Answer: normal PRI is 0.12-0.2 seconds in adults.
Represents the start of atrial depolarization to the start of
ventricular depolarization. It constitutes the beginning of the P wave
and the brief delay, or pause, before depolarization is conducted to
the ventricles. This brief pause allows the blood from the atria to
pass through the AV valves into the ventricles. (Note, this slow
conduction through the AV node is carried by calcium (Ca++) ions
◉ST Segment. Answer: Normally at the isoelectric line on the EKG.
,A horizontal, flat, and normally at the baseline level after the QRS.
Elevation or depression of 1 mm (one box) or more is considered
abnormal.
◉QT interval. Answer: Measured from the beginning of the QRS until
the end of the T wave. Represents the start of ventricular
depolarization to the end of ventricular repolarization. QT intervals
vary with HR. Precise QT interval measurements are corrected for
rate, so they are called QTc values.
REMEMBER THIS: as a rule of thumb, the QT interval is considered
normal when it is less than half of the R-to-R interval at normal rates
◉U Waves. Answer: Waves that are present in between T & p Waves
predominate if > 1-2mm or 25% of the height of the T wave
delayed purkinjie fiber re-polarization
◉Rule of 300s. Answer: find an R wave that lands on a heave line.
That's your starting point.
Then assign 300, 150, 100, 75, 60, 50 to the following heavy lines.
Wherever the next R-wave falls gives you the approximate rate.
, ◉6 second strip method. Answer: Count QRS complexes on a 6-
second strip and multiply by 10. Least accurate, provides mean rate.
◉Small square on EKG. Answer: 0.04 sec
◉Large sqaure on EKG. Answer: 0.20 sec
◉Asystole. Answer: cardiac arrest with no discernable electrical
activity
- flatline EKG
- P waves and QRS complex not present
◉Supraventricular Tachycardia (SVT). Answer: § regular but fast
rhythm
§ rate 150-250
§ P wave merged with T wave
§ PRI variable & difficult to measure
§ QRSa typically narrow
§ Common causes: stimulants, electrolyte imbalance, hypoxia
◉Atrial Fibrillation (A-Fib). Answer: § irregular rhythm
§ absent P waves and PRI
