EKG part 1 (S.G) Flashcards
SA node bpm
60-100
AV node bpm
40-60
Perkinje fibers bpm
20-40
Action Potential Phases:
-PHASE 0
- DEPOLARIZATION
- rapid influx of Na+ into cell
Action Potential Phases:
-PHASE 1
- Partial REPOLARIZATION
- Na+ channels close
Action Potential Phases:
-PHASE 2
- PLATEAU
- contraction by K+ & Ca+ into the cell
Action Potential Phases:
-PHASE 3
- REPOLARIZATION
- K+ leaves the cell
- resting membrane potential (RMP) re-established
Action Potential Phases:
-PHASE 4
- Resting membrane potential (RMP)
- Na/K pumps restored
EKG strips
-strip runs at __ mm/sec
25
EKG strips
-little box=
0.04 sec
EKG strips
-big box=
0.20 sec
PR interval represents
Atrial Depolarization
PR interval normal time
0.12-0.20 sec
QRS wave represents
Ventricular depolarization
QRS wave normal time
0.06-0.10 sec
QT interval represents
ventricular depolarize and repolarize
QT interval normal time
0.36-0.44 sec
what does a depressed T wave represent?
Ischemia
what does an elevated ST wave represent?
MI
what does a deep Q wave represent?
previous MI
What does a U wave represent?
Hypokalemia
what is Relative Refactoriness?
cells have time to repolarize and CAN respond (depolarize) from a stimulus
what is Absolute Refactoriness?
cells CANNOT respond to a stimulus
Unipolar leads
V1-V6
Bipolar leads
1, 2, 3
Augmented unipolar leads
aVr
aVL
aVf
Atrial Hypertrophy:
-PEAKED “p” wave
- p. pulmonale
- COPD
Atrial hypertrophy:
-NOTCHED “m” shaped “p” wave
- P. mitrale
- mitral stenosis
Ventricular Hypertrophy:
-wide QRS >0.10 sec
Bundle Branch Block (BBB)
