ECGs Flashcards
(25 cards)
8 steps to assess rhythm
- Heart rate
- Ventricular rhythm
- Atrial wave (p, pā, F or f waves)
- PR interval
- Identify and analyse QRS (include RR interval)
- Origin of arrhythmia
- Identify
- Evaluate it
12 Lead ECG main reason
Detect myocardial ischaemia or infarction
12 Lead frontal plane include:
Limb leads
Standard (bipolar)
- Lead I, II, III
- Lead 1 is negative (right arm) to positive (left arm) = positive deflection
Limb leads Augmented (unipolar) - Lead aVR, aVL, aVF Measure frontal plane aswell - view is two dimensional (limb leads looking into heart)
Horizontal plane 12 Lead includes:
Made up of one positive electrode and the central terminal
- Lead V1-V6
- primarily recording activity of left ventricle
aVR should be inverted?
True
What are Vectors
Vectors give an indication of movement of electrical conduction during aerial or ventricular depolarisation or repolarisation at a specific point in time
- imaginary arrow
- describes
- magnitude, Direction, Polarity
Average of all vectors is termed axis
Can calculate P,QRS, ST and T axis but QRS axis most important
What is an axis
Average of all vectors is termed axis
Can calculate P,QRS, ST and T axis but QRS axis most important
QRS axis runs diagonally from right atrium to left ventricle
How can you determine an axis deviation
Two thumb method
- overalll direction of centric depolarisation
- Lead one and two
- positive/neg
Two thumbs up norm
Left axis deviation, Lead 1 pos,Lead 2 neg, thumbs leaving each other
Right axis deviation Lead 1 neg, Lead 2 pos
Thumbs right together
When can Left axis deviation (LAD) occur?
- LV hypertrophy
- left bundle and fascicular blocks
- PVC and VT
- after an inferior MI
When can Right axis deviation (RAD) occur?
- RV hypertrophy
- right bundle branch and fasicular blocks
- PVC or VT
- after lateral MI
Myocardial ischaemia will Lead to what ecg changes
Ischaemic T waves (prolonged?)
ST elevation or depression
Myocardial Injury will lead to what ecg changes
ST segment elevation or depression
Myocardial necrosis ecg changes?
Pathological Q waves
What do t waves represent normally
- normal is showing repolarisation of epicardium to endocardium
Issues with t wave could represent ?
And description.
- delay in repolarisation
- abnormally tall, peaked or inverted
If ischaemia is in endocardium
- T wave tall and QT prolonged
Ischaemia in epicardium
- process will reverse and t wave will be inverted
ST segment elevation is a sign of?
Description of?
St segment elevation a sign of
- extensive trans mural myocardial ischaemia or injury
- > 1mm above baseline when measure 0.04 after J point (where S wave meets centre line)
- associated with pathological Q wave
- seen in the facing leads (typically depressed in reciprocal leads)
Q wave normally shows?
Normal depolarisation of IV septum from left to right
- septum is thin therefore wave is small
Pathological Q waves represent?
Definition?
- Q waves which are 25% of the depth of the succeeding R wave and/or they are greater than 0.04 seconds in width (one small square) and greater than 2mm depth-
- irreversible myocardial necrosis
- only in <50% of patients
- exceed normal height
- depth >25% of subsequent R wave
What facing leads show anterior view of heart
V1-4
What facing leads show lateral view of heart
I
aVL
V5-6
What facing leads show inferior view of heart
II
III
aVF
What facing leads show right ventricle view of heart
V4R
Right sided V4 Lead
Do any facing leads face the posterior aspect?
Lol no
What does Lisal acronym stand for?
AMI area in 12 Lead
Lateral - I and aVL Inferior - II III aVF Septal - V1-2 Anterior- V3-4 Lateral - V5-6
At least two must have stemi for it to be important
