The ECG

Question 1

what does the cardiac conducting system do and what is it made of

Answer 1

generates and transmits electrical impulses to coordinate contractions of the cardiac cycle
it is made of nodal tissue and contracting fibres

Question 2

cardiac action potential

Answer 2

cardiac myocytes depolarise to form and action potential
multiple of these cells firing at once produces a current
is different shape to muscle contraction action potential
depolarises quickly then stays depolarised for a while the repolarises

Question 3

electrical biosignals

Answer 3

electrical biopotentials can be detected at the body and be displayed

Question 4

ECG complex peak meanings

Answer 4

P wave- atria depolarisation
QRS complex- ventricle depolarisation
T wave- ventricle repolarisation

Question 5

electrical vector meanings

Answer 5

the cardiac impulse has direction and magnitude so it is a vector
vector amplitude higher/lower - greater/lesser ECG
vector towards/away electrode - ECG deflection above the line

Question 6

what is einthoven’s triangle

Answer 6

a way of connecting leads to your left, right arm and left leg with leads to form a triangle to detect heart impulses

Question 7

where does the augmented leads look at the heart from

Answer 7

aVr- right shoulder
aVl- left shoulder
aVf - from directly underneath heart

Question 8

what are the leads connected to the chest

Answer 8

V1-V6

Question 9

ECG territories

Answer 9

inferior- II,III,aVf (right conorary artery)
lateral-I,aVl,aVr,V5,V6 (circumflex artery)
anterior-V3,V4 (left anterior)
septal-V1-V2