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Phys2 ECG vector
Question | Answer |
---|---|
What are the clinical uses of a vector when looking at ECGs? | it is an arrow symbolizing the direction of depolarization that can be used for: 1.Change in heart mass (Hypertrophy). 2.Alteration of dipoles (infarction). |
Which chamber of the heart contributes the most to the MEAN QRS vector (the sum of all the vectors)? | Left ventricle, b/c it has the most mass |
what direction is septal depolarization? | Left to Right |
Where does the tail of the vector always start? Where does the tip of the vector go? | Tail: AV node. Tip: intersection of all three leads QRS amplitudes. |
What are the two methods for quantitating the direction of the vectors? | 1.Triaxial (Only leads I, II, and III). 2.Hexaxial (All 6 vertical leads) |
upward and downward QRS from a hexaxial reference: Lead I | Upward: Towards 0. Downward: Towards +180 |
upward and downward QRS from a hexaxial reference: Lead II | Upward: Towards +60. Downward: Towards -120. |
upward and downward QRS from a hexaxial reference: Lead III | Upward: Towards +120. Downward: Towards -60. |
upward and downward QRS from a hexaxial reference: aVF | Upward: Towards +90. Downward: Towards -90. |
upward and downward QRS from a hexaxial reference: aVR | Upward: towards -150. Downward: Towards +30 |
upward and downward QRS from a hexaxial reference: aVL | Upward: Towards -30. Downward: Towards +150. |
What is the normal range for a mean QRS vector on a hexaxial reference? How would the QRS of Lead I and aVF appear? | -10 to +110. (The Lower Left quadrant) **Lead 1: upwards. aVF: upwards. |
What number range would be seen with LAD (left axis deviation)? How would the QRS of Lead I and aVF appear? | 0 to -90. The Upper left quadrant. **Lead I: upwards. aVF: downward |
What number range would be seen with RAD (Right axis deviation)? How would the QRS of Lead I and aVF appear? | +90 to +180. The Lower Right quadrant. **Lead I: downward. aVF: upward |
What number range would be seen with an Extreme RAD or Northwest? How would the QRS of Lead I and aVF appear? | -90 to +180. The upper Right quadrant. **Lead I:downward. aVF: downward |
What leads should be analyzed analyzed when looking for abnormal cheat "rotations" | V3 & V4. **Right rotation: transitoin leads will be V1 and V2. **Left rotation: transition leads will be V5 and V6 **If they move towards right, rightward rotation. **If they move toward the left, leftward rotation |
What Effects will Hypertrophy have on the mean vector? | Will cause the vector to move TOWARDS the hypertrophy. |
What Effects will Infarction have on the mean vector? | Will cause the vector to move AWAY from the infarction b/c the tissue is dead. |
When would it be ok to see LAD in a patient? | OBESITY |