12 lead ECG interpretation Flashcards
Locations on body:
Lead I
Lead II
Lead III
Lead I = + on left and - on right arm
Lead II = + on left leg and - on right arm
Lead III = + on left leg and - on left arm
Locations on body
aVR
aVL
aVF
aVR = right arm
aVL = left arm
aVF = left leg
Septal infarcts are most evident in which leads
V1 and V2
___ is the dominant producer of voltage in heart
left ventricle
QRS axis points ____ and ____
QRS axis points left and posterior
normal depolarization goes in which direction
down from right arm to left leg
which leads appear + and which leads are -
+ = I, II
- = V1, V2, aVR
normal QRS axis ranges from ___ to ___
-30 to 90
what is LAD angles?
-30 to -90
LAD ALWAYS ABNORMAL
what is RAD angles
+90 to +180
CAN ALSO BE FOUND IN CHILDREN/CHEST MALFORMATION
RAD is negative in which lead
LAD is negative in which lead
RAD = neg at lead I, pos at lead II
LAD = pos at lead I, neg at lead II
thumbs up rule
which ever thumb is positive is the axis
both positive = normal axis
both negative = indeterminate
what does RBBB or LBBB or ectopic ventricular beat appear on ecg in common
widened QRS
RBBB shows as what on ecg
late R in V1 + T wave inversion in V1
large S in V6/I
LBBB shows as what on ecg
no R and large S in V1
late R in V6/1 + T wave inversion in V6
Hemiblocks cause ____ without widening the QRS
axis shifts
Hemiblocks cause axis shifts without ____
widening the QRS
___ causes LAD
blocks in anterior fascicle
____ causes RAD
blocks in posterior fascicle
What possibilies if P wave abnormalities
1) Tall P (>2.5 mm in inferior lead = R atrial enlargement)
2) Wide notch P wave with late negativity in V1 (L atrial enlargement)
what possibilities if QRS wide?
(>0.12 sec = BBB)
RBBB = large late R’ in V1 + late S wave in V6
LBBB = wide QS in V1 + wide R wave in V6
what possibilities if axis shift
Right axis = RVH or posterior hemiblock
Left axis = LVH or anteiror hemiblock
what possibilities if high voltage
ventricular hypertrophy
RVH (R wave in V1 + S wave in V6 > 11mm)
LVH (S wave in V1 + R wave in V6 > 35) + T wave inversion
what possibilities if Q waves
infarct if in 2 related leads
(25% of R wave or 0.04 sec wide)
2 contiguous leads = necrosis
what possibilities if ST elev?
injury if local
pericarditis if diffuse
what possibilities if ST depression?
ischemia
subendocardial infarct
reciprocal signs from MI (with ST elev or old MI)
what possibilities if T inversion?
ischemia (early MI)
hypertrophy
BBB
what possibilities if Long QT
electrolyte imbalance (low K, Ca2+, Mg2+
type 1A/C, type 3, congenital long QT)
late R in V1 + T wave inversion in V1
large S in V6/I
RBBB
no R and large S in V1
late R in V6/1 + T wave inversion in V6
LBBB
which BBB masks MI
LBBB
QRS is wide, think ___
BBB
QRS is narrow, think ___
hypertrophy
