ECG's Rules Flashcards
Where is the p wave originated from -
Atrial contraction generated by SA ( sino-atrial) node
Where is the PR wave originated from-
AV ( atrio ventricular) node delay
Where is the QRS wave originated from -
ventricular contraction ( generated by the Purkinje Fibres )
Where is the T wave wave originated from -
from the ventricular relaxation / repolarisation.
What is the complex in-between the s and t segment that crucial in diagnostic of a stemi
J point
Explain or describe the electrical conductivity of the heart - all electric pathways and follow of blood
SA node( positioned in right atrial ) fires - across the atria
Atria contracts * P WAVE **
Signal pass through to AV NODE this delay the signal allowing blood to fill the ventricals *** PR INTERVAL ””””
Signal passes from AV NODE to bundle of his, which splits into the bundle branches ( left and right)
This passes to the Purkinje fibre @ the apex of the heart.
The signal passes up the walls from bottom up via the Purkinje fibre - causes ventricular contraction **** QRS COMPLEX
The centrical then repolarisation occurs ** T WAVE **
THE Atrial repolarization occured during the QRS COMPLEX. - not visible due to the high charge at ventricles
What is the duration of the p wave -
0.08s ( 2-2.5 sq)
What is the duration of the PR wave -
0.12s to 0.20s (equal to 3-5sq)
What is the duration of the QRS complex -
less than 0.12s ( 3sq)
What is the duration of the QT interval -
0.36s to 0.44s (equal to 9-11 sq)
What is PPCI criteria for STEMI 🚨🚨
Limb lead - 2+ lead with elevation in 1 small box plus
Chest lead - 2+ lead with elevation in 2 small boxes plus
What are the lead views on a 12 lead ECG
Lateral - L1 avl v5 V6
Inferior - L2, L3 avf
Septal - v1, V2
Anterior- v3, v4
Non - avr
What should be suspected if st depression is seen in the anterior lead
1) what are the anterior lead cover
2) suspected is
3) test we can conduct
1) v3v4 V2 v1
2) posterior MI
3) v7, V8،v9
What test should be conducted if ST elevation is seen in the inferior lead
1) what are inferior leads
2) answer to question
3) why - what does this now mean we can’t ….
1) L2, L3 , AVF
2) V4R , take v4 and place on right side same spot.
3) if ST elevation see this mean right sided involvement (RMCA) therefore don’t give GTN due to high risk of bp drop therefore cardiac arrest
What are the two sub branches that come off the LMCA ( left main cononary artery)
LCF - left circumflex
LAD - left anterior descending
What does the LMCA ( left main coronary artery ) feed
Left ventriculal
Left atrial
And the septum
What does the right main cononary artery feed (RMCA)
Bothe ventricles
Right atrium
And the posterior portion of the heart
What is the molecules that great a electrical charge in the heart and how do they get affected once a charge arrives
Potassium ( INSIDE) the cell - maintained by pump and gated channel ( acting as a door)
Calcium + sodium outside the cell
Electric current arrives
Sodium in - causes more sodium channels to open which inturn cause positivity and open calcium channels
Calcium come bind = contraction
Cardiac axis - what lead are need to determine cardiac axis
Lead 1
Avf
Cardiac axis - what is the cardiac axis if both L1 and Avf are positive
Normal cardiac axis
What do the lead look like when it’s a normal cardiac axis
Lead 1 & avf are positive
Is the if lead 1 is positive and and avf is negative what is the cardiac axis
Left axis deviation as the leads are ** leaving**
What does left axis deviation look like
The lead are leaving
L1 is positive
Avf is negative
What does right axis deviation look like
L1 is negative
Avf is positive
** Reaching for each other **
If L1 is negative and avf is positive
What is the axis deviation
Reaching towards each other
Right axis deviation
What does extreme axis deviation look like
Both L1 & avf are negative
If both L1 and Avf are negative what is the axis deviation
Extream axis deviation
How can you identify a right bundle branch
All 3 thing must be true
1) wide qrs complex - 0.12s +
2) upright QRS complex in v1
3) slurred s waves in V6
Can turn paper on it’s right side
If the r wave faces right if not it’s facing left it’s left
How can you identify a left bundle branch block
All 3 things must be true
1) broad qrs complex - 0.12s +
2) mainly downward facing ( negative ) QRS COMPLEX in v1
3) with broad upward facing r waves in V6
4) no Q waves in v6
Turn it on it’s side ( right side ) - it’s be facing left
How can you identify a sinus tachycardia
1) heart rate above 100 but below 140
2) normal p qrs and t waves
How can you identify re- entrant tachycardia also know as narrow complex tachycardia or SVT
HR above 140
Normal qrs length
Constant rate
no p waves - as we are flying 🕊️
What is the pathophysiology of re- entrant tachycardia / svt / narrow complex tachycardia
There is a backflow of electrical activity in the atria
What is the treatment for re -enterant tachycardia / svt / narrow complex tachycardia
Vasovagal manovour - blow into something and tilt
??? Can we do as paramedic
What is the pathophysiology of wolff Parkinson white syndrome
The heart creates a new pathway from atria to centrical call the bundle of Kent which bypasses the bundle of his and av node
This causes an early depolarisation from the centrical seen as the Dela wave
What is an indicator of wolf Parkinson white syndrome on an ECG
A delta wave
This is due to early repolarisation of ventricles
This is a slight upward curve at the start of the qrs then it fly’s up
How do you identify a broad complex tachycardia or VT or ventricular tachycardia
Ventrical originating rhythm
Qrs size is 0.12s + ++++
Regular
Above 100bpm
What is known as an ectopic beat or escaped beat
This is a beat which is not generated by the SA node but from secondary cardiac pacemakers
How do you identify a 1st degree AV block
1) the PR interval has to be 0.20+ (5sq)
2) this distance must be constant, regular rhythm
What is an incomplete bundle branch block
A bundle branch block which has the morphology of a block however has a duration of less than 0.12s
What is first degree AV Block
- pr interval 0.20+
- this is constant
- followed by a qrs complex
Can be a normal variant
What is 2nd degree type 1. AV block
- pr interval 0.20+
Pr interval gradual increases distance before QRS goes missing
Type 1 runs along
What is 2nd Degree type 2 AV block
Pr interval longer than 0.20+
- pr interval constant before a random QRS complex drop off
How do you identify a broad complex tachycardia
Rate of above 100bpm
Qrs length larger than 0.12s
Regular
What is torsade debpoint and what is the key in idefinificstion
Has Long qt syndrome
R on t ( repolarisation and deoperisation happen as same time
R waves have different amplitude