[ECG made easy][ECG 1st principles] Flashcards
I, II, III, VR, VL, VF
V1-V6
Right leg lead
VL
I
II
VF
III
VR
Right ventricle
septum
anterior wall of left ventricle
Anterior wall of left ventricle
Lateral wall of left ventricle
Whichever shows the P wave most clearly (usually II)
Depolarisation towards a lead
so in V5+V6 ventricular depolarisation causes just o positive deflection. No classic ‘R’ deflection
towards
and vice versa - if the R and S waves are of equal size = depolarisation at right angles to the lead
The depolarisation wave spreads from 11 to 5 o’clock
i.e. away from VR and towards II as seen from the front
Cardiac axis
I
II (will have the biggest +ve deflection in normal axis)
III
*predominantly +ve deflections will be seen
I: -ve
II: +ve but less so
III: +ve increased and more than II
it is the predominant deflection that must be taken into account
lead II becomes predominantly -ve
(and lead III must be as well, obviously)
*usually due to conduction defect
0
90
60
120
-30
-150
-30 to +90 (VL to VF)
-30 to -90
+90 to -90 (180degrees)
R and L hypertrophy
(Right may = PE
Left may = conduction defect)
from left to right
Left - more mass.
upwards (‘R’ wave)
downwards (‘Q’ wave)
S wave - negative because the larger muscle mass of left ventricle outweighing the positive which would be seen from right ventricular depolarisation
R wave - upward deflection as the main mass of the l ventricle is depolarising towards V5/V6
Where the R and S waves are equal - indicating the position of the interventricular septum.
V3/V4
Right ventricular hypertrophy
II
The bottom strip.
electrical interference - multiple very high frequency spikes . (electric lights/bed motors or mattresses)
At the beginning of the trace. 1mV = 1cm
25 mm/s
Calm/relax/look out for parkinsons/tremor/shake
spiky baseline
especially in the limb leads
Shivering = even more pronounced spikes
- Rhythm (normal rate = 50/min
- Conduction intervals (normal/abnormal PR interval - 180ms &QRS duration - 120ms)
- Cardiac axis
- QRS description
- ST and T wave description.
yes