ECG's Rules

Question 1

Where is the p wave originated from -

Answer 1

Atrial contraction generated by SA ( sino-atrial) node

Question 2

Where is the PR wave originated from-

Answer 2

AV ( atrio ventricular) node delay

Question 3

Where is the QRS wave originated from -

Answer 3

ventricular contraction ( generated by the Purkinje Fibres )

Question 4

Where is the T wave wave originated from -

Answer 4

from the ventricular relaxation / repolarisation.

Question 5

What is the complex in-between the s and t segment that crucial in diagnostic of a stemi

Answer 5

J point

Question 6

Explain or describe the electrical conductivity of the heart - all electric pathways and follow of blood

Answer 6

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

Question 7

What is the duration of the p wave -

Answer 7

0.08s ( 2-2.5 sq)

Question 8

What is the duration of the PR wave -

Answer 8

0.12s to 0.20s (equal to 3-5sq)

Question 9

What is the duration of the QRS complex -

Answer 9

less than 0.12s ( 3sq)

Question 10

What is the duration of the QT interval -

Answer 10

0.36s to 0.44s (equal to 9-11 sq)

Question 11

What is PPCI criteria for STEMI 🚨🚨

Answer 11

Limb lead - 2+ lead with elevation in 1 small box plus

Chest lead - 2+ lead with elevation in 2 small boxes plus

Question 12

What are the lead views on a 12 lead ECG

Answer 12

Lateral - L1 avl v5 V6
Inferior - L2, L3 avf
Septal - v1, V2
Anterior- v3, v4
Non - avr

Question 13

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

Answer 13

1) v3v4 V2 v1
2) posterior MI
3) v7, V8،v9

Question 14

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 ….

Answer 14

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

Question 15

What are the two sub branches that come off the LMCA ( left main cononary artery)

Answer 15

LCF - left circumflex
LAD - left anterior descending

Question 16

What does the LMCA ( left main coronary artery ) feed

Answer 16

Left ventriculal
Left atrial
And the septum

Question 17

What does the right main cononary artery feed (RMCA)

Answer 17

Bothe ventricles
Right atrium
And the posterior portion of the heart

Question 18

What is the molecules that great a electrical charge in the heart and how do they get affected once a charge arrives

Answer 18

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

Question 19

Cardiac axis - what lead are need to determine cardiac axis

Answer 19

Lead 1
Avf

Question 20

Cardiac axis - what is the cardiac axis if both L1 and Avf are positive

Answer 20

Normal cardiac axis

Question 21

What do the lead look like when it’s a normal cardiac axis

Answer 21

Lead 1 & avf are positive

Question 22

Is the if lead 1 is positive and and avf is negative what is the cardiac axis

Answer 22

Left axis deviation as the leads are ** leaving**

Question 23

What does left axis deviation look like

Answer 23

The lead are leaving
L1 is positive
Avf is negative

Question 24

What does right axis deviation look like

Answer 24

L1 is negative
Avf is positive
** Reaching for each other **

Question 25

If L1 is negative and avf is positive
What is the axis deviation

Answer 25

Reaching towards each other
Right axis deviation

Question 26

What does extreme axis deviation look like

Answer 26

Both L1 & avf are negative

Question 27

If both L1 and Avf are negative what is the axis deviation

Answer 27

Extream axis deviation

Question 28

How can you identify a right bundle branch

Answer 28

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

Question 29

How can you identify a left bundle branch block

Answer 29

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

Question 30

How can you identify a sinus tachycardia

Answer 30

1) heart rate above 100 but below 140
2) normal p qrs and t waves

Question 31

How can you identify re- entrant tachycardia also know as narrow complex tachycardia or SVT

Answer 31

HR above 140
Normal qrs length
Constant rate
no p waves - as we are flying 🕊️

Question 32

What is the pathophysiology of re- entrant tachycardia / svt / narrow complex tachycardia

Answer 32

There is a backflow of electrical activity in the atria

Question 33

What is the treatment for re -enterant tachycardia / svt / narrow complex tachycardia

Answer 33

Vasovagal manovour - blow into something and tilt
??? Can we do as paramedic

Question 34

What is the pathophysiology of wolff Parkinson white syndrome

Answer 34

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

Question 35

What is an indicator of wolf Parkinson white syndrome on an ECG

Answer 35

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

Question 36

How do you identify a broad complex tachycardia or VT or ventricular tachycardia

Answer 36

Ventrical originating rhythm
Qrs size is 0.12s + ++++
Regular
Above 100bpm

Question 37

What is known as an ectopic beat or escaped beat

Answer 37

This is a beat which is not generated by the SA node but from secondary cardiac pacemakers

Question 38

How do you identify a 1st degree AV block

Answer 38

1) the PR interval has to be 0.20+ (5sq)
2) this distance must be constant, regular rhythm

Question 39

What is an incomplete bundle branch block

Answer 39

A bundle branch block which has the morphology of a block however has a duration of less than 0.12s

Question 40

What is first degree AV Block

Answer 40

• pr interval 0.20+
• this is constant
• followed by a qrs complex

Can be a normal variant

Question 41

What is 2nd degree type 1. AV block

Answer 41

• pr interval 0.20+
  Pr interval gradual increases distance before QRS goes missing

Type 1 runs along

Question 42

What is 2nd Degree type 2 AV block

Answer 42

Pr interval longer than 0.20+
- pr interval constant before a random QRS complex drop off