ECGs Revisited Flashcards
What part of ECG equipment is an electrode?
The thing that sticks onto your chest
What part of ECG equipment are the cables/wires?
The wires connected to the electrodes
What part of ECG equipment are the leads?
They are the views of the heart
How are vectors represented?
By arrows
In what direction will a charge travelling towards a negative electrode travel?
Down
In what direction will a charge travelling towards a positive electrode travel?
Up
What direction is the charge travelling if the line is isoelectric?
Perpendicular to both the anode and the cathode
What does the steepness of the electrode denote?
The velocity of the action potential
What does the width of the deflection denote?
The duration of the event
How does the thickness of the muscle affect deflection?
Thinner muscle creates a smaller deflection
How many limb leads and how many chest leads are there?
3 limb leads
6 chest leads
What rule is used to remember where the leads go? How does it work?
Rule of Ls
Lead 1= one L= right arm to Left arm
Lead 2= two Ls= right arm to Left Leg
Lead 3= Left arm to Left Leg
For the leads, what rule is used to work out which is the anode and which is the cathode? How does it work?
The rule of reading
In english we read from left to right and up to down
For each lead either go left to right or up to down and always start with the anode
Where exactly is V1 placed?
4th intercostal space at right border of the sternum
Where exactly is V2 placed?
4th intercostal space at the left border of the sternum
Where exactly is V3 placed?
Between V2 and V4
Where is V4 placed?
5th intercostal space at the mid clavicular line on the left
Where exactly is V5 placed?
5th intercostal space at the anterior axillary line on the left (same level as V4)
Where exactly is V6 placed?
5th intercostal space at the mid axillary line on the left (same level as V4 and V5)
Which leads can be referred to as the chest leads?
V1, V2 and V3
Which leads look at a lateral view of the heart and what vessel does this correspond to?
I, avL, V5 and V6
Left circumflex
Which leads look at a septal view of the heart and what vessel does this correspond to?
V1 and V2
Left anterior descending
Which leads look at an anterior view of the heart and what vessel does this correspond to?
V3 and V4
Left anterior descending
Which leads look at a inferior view of the heart and what vessel does this correspond to?
II, III, avF
Right coronary artery
What are the 3 main arteries that supply the heart? Include their abbreviations
Left circumflex (Lcx)
Left anterior descending (LAD)
Right coronary artery (RCA)
What are the 2 different types of ECG leads?
Limb leads- they use the limbs (right/left arm and left foot)
Chest leads- V1-V6 placed on the chest
Which leads are bipolar and which are unipolar?
Limb leads are bipolar, chest leads are unipolar
What leads lie in the coronal plane?
Leads I, II, III, aVf, avL, avR
What leads lie in the horizontal plane?
V1-V6
Are V1-V6 anodes or cathodes?
Cathodes
How many milliseconds are in a second?
1000
What do you need in order to find the cardiac axis?
2 leads that are perpendicular to each other
Explain how to cardiac axis is calculated?
The QRS vector for both perpendicular leads must be calculated. Then create a triangle, find the missing angle and subtract from 90 if it needs to be adjusted
What leads are the augmented limb leads?
avR, avL, avF
How are the vectors for the cardiac axis calculated?
Count how many squares up the QRS complex goes
Count how many squares down the QRS complex goes
Vector= squares up- squares down
It could be negative or positive
