Lec 3 - ECG Flashcards
What does an ECG do
detects electrical activity of cell mass, detects electrical changes within the myocardium,
what info can be derived from an ECG
heart rate, heart rhythm, conduction times across the heart, location of ischaemic damage
a wave of depolarisation travelling towards a positive electrode results in a
positive deflection in the ECG trace
a wave of depolarisation travelling away from a positive electrode results in a
negative deflection
a wave of repolarisation travelling towards a positive electrode results in a
negative deflection
a wave of repolarisation travelling away from a positive electrode results in a
positive deflection
the voltage amplitude is directly related to the
mass of tissue undergoing depolarisation or repolarisation
what is needed to produce a 12 lead ecg
limb leads, chest leads, augmented limb leads
the six limb leads include
leads 1, 2, 3, aVR, aVL and aVF
which leads are bipolar
leads 1, 2 and 3 - two recording electrodes are used
which leads are unipolar
aVR, aVL, aVF
what are the six unipolar chest leads?
v1-v6
what is the cardiac axis
The axis of the ECG is the major direction of the overall electrical activity of the heart.
what are some causes of axis deviation
position of heart, hypertrophy, infarcted tissue, conduction problems
what does the p wave represent
atrial depolarisation
