EKG/ACLS Flashcards
P Wave
Represents Atrial Depolarization
Normal: Upright and smooth
Abnormal
P wave: Saw tooth pattern
Atrial Flutter
No definable P wave
Atrial Fibrillation
Inverted P wave
Retrograde conduction from the AV node
Notched- biphasic P Wave
Atrial Hypertrophy
PR Interval Definition
Time of onset from Atrial Depolarization to the onset of Ventricular Depolarization. Ie: the time for the atrial impulse to reach the ventricles.
Measured from the beginning of the P wave to th beginning of the Q (or the R if there is no Q)
Normal PR Interval time
0.12-0.20 seconds
Abnormal PR Interval- Prolonged
Delayed conduction through the AV node
QRS Complex Definition
Ventricular Depolarization
Ie: The spread of the impulse through the ventricular muscle.
Q Wave
The first negative deflection of the QRS before the R
R Wave
Any positive deflection in the QRS
S Wave
Negative deflection after the R wave
Normal QRS complex time
0.04-0.12 seconds
Abnormal QRS
- Deep widened Q wave
- Notched or “rabbit ear” configuration (BBB)
- Broadened QRS (greater than 0.12 sec: intraventricular conduction defect
ST Segment
Early ventricular repolarization
Pause after the QRS
Normal ST Segment
Isoelectric
Abnormal ST segment: Elevated
Indicates myocardial injury
Abnormal ST segment: Depressed
Indicates myocardial ischemia (spooning-dig)
T wave
Ventricular Repolarization
Normal T wave description
Smooth, rounded, larger than a P wave
Abnormal T wave: Inverted
Myocardial ischemia
Abnormal T wave: Flattened or inverted
Hypokalemia
Abnormal T wave: Tall or peaked
Hyperkalemia
Abnormal T wave: Notched
Pericarditis
