| Question |
 |
|
| Answer |
|
|
| Cellular electrophysiologists measure potentials by |
measuring the inside of the cell with respect to the outside of the cell |
| Electrocardiographers depend on |
Surface electrodes |
| Measurements are recorded as the ________ between two electodes |
Potential difference |
| When the depolarizing wave approaches the positive electrode, the deflection is _______ |
upward |
| Fully Depolarized |
All positive inside
all negative outside |
| Repolarization occurs in the _________ direction |
opposite |
| The last to depolarize is the __________ to repolarize. |
first |
| Sequence of electrical activation and teh ECG |
Endo -> Epi -> Apex -> Base |
| Q wave |
depolariztion of the sepum |
| P wave |
depolarization of the atria |
| S |
Late lateral depolarization of the left base
|
| ST segment |
Full depolarization |
| T |
repolarization |
| U |
Late repolariztion of mid cells in myocardium |
| QRS |
Ventrical depolarization |
| PR segment |
time between atrial activation and ventricular activation |
| If conduction is slowed through the AV node, what happens to the PR interval? |
Lengthens |
| Bundle Branch Block |
Wide QRS |
| cardiac ion channelopathies that can lead to long _____________ |
QT intervals |
| Lead I |
+ left arm
- right arm |
| Lead II |
+ Left Leg
- Right arm |
| Lead III |
+ left leg
- left arm |
| aVF |
+ left foot
- Head |
| aVR |
+ right arm |
| aVL |
+ left arm |
| Downward deflection of QRS normal in lead |
aVR |
| Horizontal plane |
V1-V6 |
| Interpretation of ECG |
rate
rhythm
vector in frontal plane
hypertorphy
infarction |
| Rate = |
(60s/min) / R-R interval |
| Large box = |
.2 seconds |
| 1 Large box |
300 bpm |
| 2 large box |
150 bpm |
| 3 large box |
100 bpm |
| 4 large box |
75 bpm |
| 5 large box |
60 bpm |
| 6 large box |
50 bpm |
| LAD |
I = upward
aVF = Downward |
| Normal axis |
I = upward
aVF = upward |
| RAD |
I = downward
aVF = upward |
| Extreme RAD/LAD |
I = downward
aVF = downward |
| I |
0 degrees |
| II |
60 degrees |
| III |
-60 degrees |
| avF |
90 degrees |
| avL |
-30 degrees |
| avR |
-150 degrees |
| Quick and easy devation method |
1. find isoelectric line
2. find vector that is perpendicular....is it up or down?
3. up is positive vector down is negative vector |
| Hypertrophy vector movement |
vector moves toward hypertrophy |
| infaction vector movement |
vector moves away infarction |
HHS Shrek
