ECG Flashcards
Describe the placement of limb leads
Red: right arm
Yellow: left arm
Green: left foot
Black: right foot
Describe the different views provided by limb leads
LI (RA - LA): 0 d
LII (RA - LF): 60 d
LIII (LA - LF): 120 d
aVF: 90 d
aVL: -30 d
aVR: -150 d
Describe the placement of chest leads
V1 (red): 4th IC space, R sternal edge
V2 (yellow): 4th IC space, L sternal edge
V3 (green): between V2 and V4
V4 (brown): 5th IC space, mid-clavicular line
V5 (black): between V4 and V6
V6 (purple): 5th IC space, mid-axillary line
Which leads show anterior heart
V3, V4
Which leads show inferior heart
LII, LIII, aVF
Which leads show septum
V1, V2
Which leads show lateral heart
LI, aVL, V5, V6
ECG wave upstroke shows…
Depolarisation towards or repolarisation away from positive electrode
ECG wave downstroke shows…
Depolarisation away from or repolarisation towards positive electrode
What does each segment of the ECG wave show
P wave: atrial depolarisation
PR segment: AVN 120ms delay and bundle of His depolarisation
Q: septum depolarisation (from L to R)
R: ventricular depolarisation (from endo to epicardium)
S: ventricular base depolarisation (towards atria)
ST segment: delay to ensure complete depolarisation
T wave: ventricular repolarisation (epi to endocardium)
how may small and large squares make 1 sec
5 large squares
25 small squares
1 large square and 1 small square = how many seconds
1 large square = 0.2 secs
1 small square = 0.04 sec
how is HR calculated if it is regular? irregular?
Regular: no. of large squares in R - R interval, divided by 300
Irregular: no. of QRS in 30 sqrs (i.e. 6 secs) x 10
how is presence of sinus rhythm determined
- is rhythm regularly regular?
- what is HR?
- are P waves present and are they upright in leads I and II?
- is PR interval normal (3-5 small sqrs)?
- is every P wave followed by QRS and every QRS followed by P wave?
- is QRS normal width (<3 small sqrs)?
