ECG's Rules Flashcards
(116 cards)
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 and how does this correspond to complexes seen on ECG
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 -
Bonus points what is the normal QTC
0.36s to 0.44s (equal to 9-11 sq)
QTC sgpuld be less than 500ms
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 - how to conduct
3) why - how does this effect the treatment plan
1) L2, L3 , AVF
2) V4R , take v4 and place on right side same spot.
3) if ST elevation see this mean right ventricular involvement (RMCA) therefore caution in give GTN +morphine due to high risk of bp drop reduced cardiac output + venous return 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 create 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
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 **