ECG Flashcards
What does a lead do?
Measures difference in potential at two points
Where does lead I go?
RA -ve to LA +ve
Where does lead II go?
RA -ve to LL +ve
Where does lead III go?
LA -ve to LL +ve
What does depolarisation towards the electrode cause?
Upward deflection in the ECG
What does depolarisation away from the electrode cause?
Downward deflection in the ECG
Which limb leads are bipolar?
Standard
Which limb leads are unipolar?
Augmented
What is the polarity of the augmented limb leads?
One positive electrode with the two others linked as negative
What is important to remember about aVR?
It is always inverted
Which plane do the chest leads work in?
Axial
How many electrodes are in a 12 lead ECG?
9
What does the ST segment correspond to?
Systole- ventricles contract
What does the TP segment correspond to?
Diastole- ventricles relax
What would be the next test to do in suspected intermittent rhythm disturbance?
Ambulatory ECG for 12 hours or 7 days
What would be the next test to do for stable angina?
Exercise ECG
Where should V1 be placed?
4th IC space, right sternal angle
Where should V2 be placed?
4th IC space, left sternal angle
Where should V3 be placed?
Halfway between V2 and V4
Where should V4 be placed?
Apex beat- 5th intercostal space midclavicular line
Where should V5 be placed?
Anterior axillary line
Where should V6 be placed?
Mid axillary line
How long does one large box correspond to?
0.2 secs
How long does one small box correspond to?
0.04 secs
What does the p wave represent?
Atrial depolarisation