Download ر ن الرحيم ر يم بسم ﷲ الرحمن ر ن ب م ب م

25/01/1432
ELECTROCARDIOGRAM "ECG“
"ECG“
Physiology Department
Cairo University
‫الرحيم‬
‫يم‬
‫ن ر‬
‫الرحمن‬
‫بسم ﷲ ر‬
‫ب م‬
2010--2011
2010
3
41-
2
1
Regarding the causes of the ECG
waves
all
the
following
are
correct
EXCEPT:
a- P wave by atrial depolarization
a
depolarization.
b- QRS complex by ventricular depolarization.
c- T wave by ventricular repolarization.
d- U wave by papillary muscle depolarization.
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40- In the fundamental rules of the ECG all
the following are right EXCEP:
a- It is a biphasic record of myocardial action
potential fluctuations.
b- Deflection record occurs only during complete
depolarization or repolarization.
c- +ve wave occurs when depolarizing current
approaches the +ve terminal electrode of the
meter.
d- -ve wave happens when repolarizing current
approaches the +ve terminal electrode.
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42- The causes of the ECG “intervals”:
a- PR by AV nodal conduction.
LF arm
RT arm
b- ST by atrial repolarization.
c- QT by ventricular depolarization and ventricular
repolarization.
d- All of the above.
RT leg
LF leg
+ Terminal
Electrode
Einthoven's triangle:
- A triangle with the heart at its center.
- obtained from the three standard limb leads record.
- Zero potential is obtained if the 3 electrodes are connected
to a common indifferent electrode.
2
+ Terminal
Electrode
+ Terminal
Electrode
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1
2
3
aVR
+ Terminal
Electrode
aVL
+ Terminal
Electrode
aVF
+ Terminal
Electrode
+ Terminal
Electrode LI
V6(+ve)
Last
Depolarization
-ve to +ve current
3
1st
V1(+ve)
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+ Terminal
Electrode LI
1st
Repolarization
+ve to –ve current
Different QRS complex nomenclatures
“Growing R"
2
1
1
1
2
4
V3(+ve)
Last
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2
1
1
2
1
V4(+ve)
45- Axis of the heart is:
44- The voltage of the ECG:
a- Mean instantaneous vector of QRS complexes in
a- Is normal summation of QRS complexes in
vertical plane.
b Normally
bN
ll from-30
f
30 to
t +60.
+60
b Normally
bN
ll equals
l <1.5
<1 5 mV.
V
c- Deviated to left side in full term pregnant woman.
c- Is low in an individual having body mass
d- Deviated to right side in long slender person
(e.g., +80).
5
standard limb leads.
index (BMI) 35.
d- All of the above.
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47- The configuration of QRS complex in
normal ECG:
a- Depends only on the direction of depolarizing
current.
b- Is mainly positive in right ventricular surface
pattern.
c- Exhibits growing R in chest leads.
46- The P-wave of normal ECG:
a- Has voltage and duration nearly equal 2.5 × 2.5
mm.
b Is
bI upright
i ht in
i aVR.
VR
c- Represents right atrial depolarization in its
second half.
d- Coincides with atrial systole.
d- Is positive in aVR.
48- As regards Q wave all the following are
49- In normal ECG:
a- The average duration of QT interval is 0.50 sec.
b- The ST segment is an isoelectric line.
c- The T wave is rounded and symmetrical.
d- The height of the T wave is > 10 mm in chest
leads.
correct EXCEPT:
a- Represents septal depolarization from left to right
in V5.
b Its depth is not more than 1/4 its corresponding
bR.
c- Its duration is not more than 0.04 sec.
d- Is deep and wide in recent myocardial infarction.
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