st segment monitoring Flashcards
lateral wall MI seen in
1, avl, v5, v6
inferior wall MI seen in
2, 3, avf (supplied by RCA)
anterior seen in
v3 v4 (LAD)
septal wall
v1 v2 (LAD septal branches)
most useful lead to detect arrhythmias
lead 2
p wave atria
depolarization beings
PR atria
depolarization complete
QRS atria
repolarization
QRS ventricle
depolarization beings
ST ventricle
depolarization complete
T ventricle
repolarization beings
after T wave ventricle
repolarization complete
ST segment MI if elevation or depression is greater than
1mm
the heart repolarizes from ___ to ___ and ___ to ___
apex to base and epi to endo
the myocytes fo from
+ to -
RCA shown on
2, 3, avf
circumflex shown on
1, avl, v5, v6
LAD shown on
v1 v2 v3 v4
the mean electrical vector tends to point toward ___ and away from ___
towards areas of hypertrophy, away from areas of MI
right axis deviation
1 pointing down and aVF pointing up
left axis deviation
1 pointing up and AVf pointing ddown
normal axis is between
-30 and 90
left axis dev is more neg than
-30
right axis dev is more pos than
90
what causes right axis dev
COPD , bronchospasm, cor pulmonale, pulm hin, PE
what causes left axis dec
chronic htn, LBBB, aortic stenosis, aortic insufficiency, mitral regurg
Einthoven’s law
if electrocardiograms are taken simultaneously with the three limb leads, at any given instant the potential in lead II is equal to the sum of the potentials in leads I and III.
rca supplies
RA and RV
L circumflex supplies
LA and LV
LAD supplies
RV, LV, septum
posterior wall infarct
V1 V2depression, v7 v8 v9 elevation.
bipolar leads read from
negative to positive
which leads are the bipolar leads
1, 2,3 (limb leads) neg to pos
which leads are the augmented leads
avr avl avf
augmented leads read from
center to specific positive lead and are unipolar
precordial leads (v1-v6) are
unipolar (from center to positive outward)
which lead for monitoring of ST in order
v3 v4 v5 2 avf
which lead is good for assessment of narrow QRS complex rhythms and p wave
lead 2
nagelhout recommends for 5 cable system
v3 mcl5 avf
nagelhout recommends for 3 lead system
mcl5 avf
where is LA placed
manubrium
where is V placed
lower body of sternum
where is LL placed
left midaxillary
RA placed
right midaxilary
RL
any convenient location
right arm
negative negative
left arm
positive negative
LL
postitive positive
12 lead RA
over the outer R clavicle
12 lead LA
over the outer L clavicle
12 lead LL
near the iliac crest or midway between the costal margin and left iliac crest, anterior axilally line
12 lead RL
at any conveienent location, upper right shoulder
12 lead v1
fourth intercostal space right of sternal border
12 lead v2
fourth intercostal space left of sternal border
12 lead v3
equal distance between v2 v4
12 lead v4
midclavicular line at fifth intercostal space
12 lead v5
horizontal to v4 on the anterior axillary line, or midway between v4 v6
12 lead v6
horizontal to v5 on midaxillary line
12 lead v7
horizontal to v6 on posterior axillary lie
12 lead v8
horizontal to v7 below the left scapula
12 lead v9
horizontal to v8 at the left paravertebral border
isoelectric line
PR segment
st threshold in leads v2 and v3
-.5mm
a depressed ST segment has greater __ than an upscoping depressed ST segment
specificity
lead 1 Is formed by
left arm + , right arm -
lead 2 is formed by
right arm - to left leg +
lead 3 is formed by
left arm+ , left leg +
