lead 2 is in parralell to the axis of the heart which makes it get a really nice view of the electrical activity in the heart

V5 and V6 = view of lateral heart

the very beginning of the P wave is = to depolarisation of the SA node

P wave represents = atrial depolarisation

(start of P - start of Q) PR interval represents the delay in the AV node since the SA node depolarised this is 120-200ms (total time it takes to travel from SA to AV) this ensures that the atria and ventricle dont contract at the same time

if the PR interval is lengthened it means there is a delay and this suggests heart block

QRS = ventricular depolarisation

Q wave =

QR = transduction of signal down the heart

RS = transduction of signal up the punkinje fibres

T wave - ventricular depolarisation