EKG Fundamentals Flashcards
Electrical alternans is an electrocardiographic phenomenon in which the ______ varies between heart beats.
QRS amplitude
Normal PR interval
less than 0.2s (200ms)
Normal QRS
Less than 0.12s (120ms)
3 small boxes
Normal QT interval for men and women
men: less than 0.43s (430ms)
women: less than 0.46 (460ms)
1 large box is how many mm
5mm
1 small box is how many mm and seconds
1mm, 0.04seconds
1 small box is how tall, how many mV
1mm, 0.1mV
Prolonged QT increased risk of?
polymorphic tachycardia
Upward deflection occurs when the flow does what?
- Depolarization - the flow of positive charges Approaches the positive electrode
- Repolarization - the flow of negative charge Approaches the negative electrode
Downward deflection occurs when the flow does what?
the flow of positive charge Moves Away from the positive electrode
Which electrode is considered the eye? Moving away or towards the eye produces what deflection?
Positive Electrode
Moving towards the eye, positive deflection
Moving away from the eye, negative deflection
Describe the position of Lead II and flow movement
RA –> LL
RA: Negative Electrode
LL: Positive Electrode
Describe the position of Lead I and flow movement.
RA –> LA
RA: Negative Electrode
LA: Positive Electrode
Describe the position of Lead III and flow movement.
LA –> LL
LA: Negative Electrode
LL: Positive Electrode
What is the most common lead used in a rhythm strip of the 12-lead EKG
Lead II
Atrial depolarization is what waveform
P wave
AV node depolarization is what waveform
PR segment. No net movement of charge.
What are the two roles of the AV node
- Slow conduction of SA node impulses - holds charge 0.1s (100ms)
- Intrinsic rate of 40-60 beats for second
Q wave is indicative of?
Septal depolarization
What portion of the electrical conduction system depolarizes the interventricular septum
Left Bundle
Depolarization of the apex of the ventricles is what waveform?
R wave