ECG II Flashcards
What are the 3 things we can get from the EKG?
Rate
Perfusion
Rhythm
What is the A-H interval?
Time from initial rapid deflection of atrial wave to initial rapid deflection of his bundle potential
What does the A-H interval tell us?
It approximates the conduction time through the a-v node
NORMAL: 50 - 120 msec
What does the H-V interval?
Time from initial deflection of his bundle potential and the onset of ventricular activity
NORMAL : 35 - 45 msec
What are some variables that effect ECG?
Cardiac generator (site of depolarization)
Cardiac electrical fields (tissue that surrounds heart)
Body surface potentials (Leads, amplifiers, displays)
ECG recording and interpretation
Einthoven’s Triangle is also known as what?
Axis of Acquisition
Lead I is what?
RA (-) ——-> LA (+)
When a wave of depolarization goes from - to +, this portrays what on the ECG waveform?
Upward slope / positive deflection
RA (-) ———> LL (+)
Lead II
Lead III?
LA (-) ———-> LL(+)
Electrical impulses that travel perpendicular to the lead axis show what on the ECG waveform?
Equiphasic deflection (half up and half down)
or
Straight line recording
Electrical impulses that travel away from the positive electrode show what on the ECG waveform?
Negative deflection
Which lead is the horizontal lead of the triangle?
Lead I
According to the triaxial reference system, what degrees are associated with Lead I?
0 and 180
According to the triaxial reference system, Lead II is associated with what degrees?
+60 and -120
According to the triaxial reference system, what degrees are associated with Lead III?
+120 and -60
For ventricular activity, a downward stroke (negative deflection) could represent which waves?
Q or S wave
What would an upward stroke for ventricular activity represent?
R wave
LOOK AT the DRAWINGS from powerpoint to get better idea of pics
I’m doing my best trying to make questions from them but proving difficult
JUST REMEMBER I AM ASKING QUESTIONS REGARDING LEAD II
The start of the P-wave to p-wave peak represents what?
S-A node to A-V node atrial depolarization
The delay of the A-V node is showed by what of ECG waveform?
P-wave peaking to return to baseline
The Q waves negative deflection represents what?
Septal depolarization
Apical and L ventricular depolarization are shown as what on ECG waveform?
End of Q wave to peak of R wave
What begins the downward deflection of the R wave?
Late L ventricular depolarization
The T wave is shown because of what ?
Ventricular repolarization
T or F: The last portion of the heart to depolarize is the first to repolarize
TRUE
what causes positive deflection/upstroke in T wave
T or F: Standard ECG limb lead positioning should be inside the cardiac borders?
FALSE
should be outside the cardiac borders
What is Einthoven’s Law?
In the ECG, the potential of any wave or complex in lead II is equal to the sum of the potentials of leads I and III
II = I + III
Augmented vector leads are unipolar or bipolar?
UNIPOLAR
Limb leads are unipolar or bipolar?
BIPOLAR
AVF is what?
Augmented vector lead of the foot
AVR is what?
Augmented vector lead of right arm
AVL is what?
Augmented vector lead of left arm
Vector leads use what kind of configuration?
Wilson configuration
2B - A - C / 3
Augmented vector leads use what kind of configuration?
Goldberger configuration
2B - A - C / 2
In augmented vector leads, the augmented lead is always which electrode?
The positive electrode
What degrees are associated with aVL?
-30
What degrees are associated with aVR?
-150
What degrees are associated with aVF?
+90
How does Sub Q emphysema effect the vectors ?
SOMEONE WHO KNOWS PLEASE PLACE IN HERE
How does thoracic pressure effect the vectors?
SOMEONE WHO KNOWS PLEASE PLACE IN HERE
Know the Hexaxial reference system
I dont know how to put pics in here so if someone wants place it in here
Chest (precordial) leads are unipolar or bipolar?
Unipolar
Bipolar leads give projections in what planes?
Frontal plane
transverse plane
(even sometimes sagital plane)
Unipolar leads give projections in what planes?
Transverse plane
V1 leads goes where?
4th intercostal space, right margin of sternum
V2 leads goes where?
4th intercostal space, left margin of sternum
V3 leads goes where?
Midway between V2 and V4
V4 leads goes where?
5th intercostal space, midclavicular line
V5 leads goes where?
5th intercostal space, anterior axillary line
V6 leads goes where?
5th intercostal space, midaxillary line
Blood is only perfused in the ventricles during what?
Diastole
Which is best lead to determine LV ischemia and/or dysfunction
V5
though according to BIggs today new information says V4 so look for both on test
What are other options are determining LV ischemia other than V5?
V4 and V6
What is the maximum pressure in the aorta during systole?
Always less that pressure inside left ventricle
When using the EASI electrode configuration, what are the location of each?
E - end of sternum
A - L Axilla
S - Sternal notch
I - R Axilla
If you are using EASI electrode configuration, what EKG waveform are you mimicking?
Pre-cordial leads
The Cardiac vector (mean QRS axis) is associated with what degrees?
-45
If the cardiac vector closely parallels the axis, amplitude will be large or small?
VERY LARGE
Which compartment of the heart is under the greatest stress?
Why is this?
Left ventricle
b/c it contains greatest contractility strength
Which ventricle is at most risk for ischemia?
LV b/c it is the hardest to get blood flow to and it requires the most 02 because its the largest
What is perfusion pressure?
Perfusion pressure = pressure going in - pressure going out
T OR F: LV perfusion has nothing to do with valves?
TRUE
