| 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 |
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