EKG 101 Flashcards
SA node
pacemaker of the heart and where the cardiac conduction pathway begins
AV node
“HOLDS” onto the impulse for a short period of time so that the atrium can contract before the ventricles
P wave
represents “ATRIAL” depolarization as electricity travels from the SA node to the AV node
R wave
represents electrical activity travelling from the AV node, down the Bundle of His
S wave
the EKG represents electrical activity travelling “up” the purkinje fiber
The QRS complex
represents ventricular depolarization.
T wave
repolarization of the heart
The PR segment
the “time” that the AV node is holding onto the impulse
The ST segment
the “time” between ventricular depolarization and the heart repolarizing
Function of the Bundle of His
runs through the interventricular septum to quickly get the impulse
to the bottom of the heart
Function of the Purkinje fibers
wrap up both sides of the ventricles and cause them to contract
from bottom to top to squeeze blood into the pulmonary vein and aorta
The AV node is located in the
Atria (junction)
1st degree AV block
consistently prolonged PR interval with no dropped beats (no intermediate intervention needed)
2nd degree Type 1 block
Also called a Wenckebach block or Mobitz Type 1 block
2nd degree Type 1 AV block
ever elongating PR interval and then dropped beat (no intermediate intervention needed)
2nd degree Type 2 AV block
consistent PR interval with dropped beats (treat only symptomatic with pacemaker )
3rd degree AV block
complete AV node failure not a weakening. consistent P waves and consistent QRS complexes with no correlation between them (pacemaker usually installed for symptomatic cases)
Bundle branch block
wide QRS complex and can make STEMI identification difficult (no intervention needed)
The AV nodes purpose is to:
Delay conduction into the ventricles
The AV nodes action is displayed on the EKG as the:
PR interval
Clinically significant, unstable AV blocks are often treated prehospitally with:
Transcutaneous pacing
What does Automaticity refer to?
refers to the heart’s cells all having the ability to depolarize and generate electrical impulses (usually takes place if the SA node fails- safety measure)
Describe Junctional rhythms
inverted or absent P waves with narrow QRS complexes
40-60 BPM
Describe Ventricular rhythms
wide QRS complexes
20-40 BPM
Determine Rate
determined by counting the QRS complexes in a six second strip and multiplying by 10
What does a Prolonged PR interval represent?
a block in the AV node
ST segment elevation or depression gives a clue in which?
a possible myocardial ischemia or infarction
3 types of rhythms
- Sinus (60-100 bpm)
* Upright P wave
* Narrow QRS - Junctional (40-60 bpm)
* Inverted or absent P wave
* Narrow QRS - Ventricular (20-40 bpm)
* No P wave
* Wide QRS
3 types of rhythms
- Sinus
* Upright P wave
* Narrow QRS - Junctional
* Inverted or absent P wave
* Narrow QRS - Ventricular
* No P wave
* Wide QRS
5 Steps of EKG Interpretation
- Rate (speed of the rhythm)
- Rhythm regular vs. irregular) measure time between beets
- presence of P waves (inverted, PR- interval length, elongated
- The Width of the QRS complex
- ST elevation (infarction) or depression (ischemia)
The three “neighborhoods” a rhythm can be generated from are:
- Sinus Rhythm
- Junctional Rhythm
- Ventricular Rhythm
True or False:
A fib is worse than V fib?
false
