? Introduction
? History
? Normal ECG
--- Content provided by FirstRanker.com ---
? Procedure? Limb Leads
ECG, EKG
--- Content provided by FirstRanker.com ---
It is the procedure of recording the electrical activity of the heart. The
electrode combination records the difference of potential difference at two
--- Content provided by FirstRanker.com ---
sites on the body. The potential differences are produced due to the electricalactivity of the heart.
Electrocardiograph is the machine
--- Content provided by FirstRanker.com ---
Electrocardiogram is the record
The characteristic shape and timing of the ECG waves are due to the spread
--- Content provided by FirstRanker.com ---
of wave of depolarization and repolarization associated with each heart beat.? The ECG is not
--- Content provided by FirstRanker.com ---
only the oldestbut, in fact, over
100 years after
--- Content provided by FirstRanker.com ---
its introduction,
continues as the
--- Content provided by FirstRanker.com ---
most commonlyused
cardiovascular
--- Content provided by FirstRanker.com ---
laboratory
procedure.
--- Content provided by FirstRanker.com ---
What does the ECG look like?Waves
--- Content provided by FirstRanker.com ---
R
T
--- Content provided by FirstRanker.com ---
PQ
S
--- Content provided by FirstRanker.com ---
Electrocardiogram waves
? P-wave ? depolarization of atria
--- Content provided by FirstRanker.com ---
? Atria begin contracting about 25msec after the start ofthe p-wave
? QRS-complex ? ventricular depolarization
--- Content provided by FirstRanker.com ---
? Ventricles begin contracting shortly after the peak of
the R wave
--- Content provided by FirstRanker.com ---
? T-wave ? ventricular repolarizationElectrocardiogram intervals/segments
--- Content provided by FirstRanker.com ---
? Segments ? extend from the end of one wave tothe start of another
? P-R interval: start of atrial depolarization to start
--- Content provided by FirstRanker.com ---
of QRS
? Q-T interval: time required for ventricles to
--- Content provided by FirstRanker.com ---
undergo a single cycle of depolarization andrepolarization; measured from end of P-R to end
of T
--- Content provided by FirstRanker.com ---
Instantaneous potentials developed
on the surface of a cardiac muscle mass
--- Content provided by FirstRanker.com ---
Recording depolarization
and repolarization waves
--- Content provided by FirstRanker.com ---
Flow of current in the chest aroundpartially depolarized ventricles
Generation of dipole over heart
--- Content provided by FirstRanker.com ---
+ + + ++ + + +
+ + + +
--- Content provided by FirstRanker.com ---
+ + + +
+ + + +
--- Content provided by FirstRanker.com ---
+ + + ++ + + +
+ + + +
--- Content provided by FirstRanker.com ---
-
- - + +
--- Content provided by FirstRanker.com ---
+ + + +- + + +
+ + + +
--- Content provided by FirstRanker.com ---
+ + + +
+ + + +
--- Content provided by FirstRanker.com ---
+ + + ++ + + +
+
--- Content provided by FirstRanker.com ---
If the polarity is reversed?+
- - + +
--- Content provided by FirstRanker.com ---
+ + + +
- + + +
--- Content provided by FirstRanker.com ---
+ + + ++ + + +
+ + + +
--- Content provided by FirstRanker.com ---
+ + + +
+ + + +
--- Content provided by FirstRanker.com ---
--
- -
--- Content provided by FirstRanker.com ---
- - + + + +
-
--- Content provided by FirstRanker.com ---
- + + + + +-
- - - +
--- Content provided by FirstRanker.com ---
+ + + +
- + + +
--- Content provided by FirstRanker.com ---
+ + + ++
-
--- Content provided by FirstRanker.com ---
- -- - - -
- -
--- Content provided by FirstRanker.com ---
-
- - - - -
--- Content provided by FirstRanker.com ---
+ +-
- - - - - + +
--- Content provided by FirstRanker.com ---
- - - - - - + +
+
--- Content provided by FirstRanker.com ---
-- -
- - - -
--- Content provided by FirstRanker.com ---
- -
-
--- Content provided by FirstRanker.com ---
- - - - -- -
-
--- Content provided by FirstRanker.com ---
- - - - -
- -
--- Content provided by FirstRanker.com ---
- - - - - -- -
+
--- Content provided by FirstRanker.com ---
RememberThe representation of the electrical activity of the
heart is critically dependent on the
--- Content provided by FirstRanker.com ---
position of the electrodes. The same electrical
activity will look different on different electrode
--- Content provided by FirstRanker.com ---
combinationsA combination of electrodes for recording is called a LEAD
Leads that are routinely used for standard 12 lead ECG
--- Content provided by FirstRanker.com ---
Standard Limb Leads
Wilhem Einthoven
--- Content provided by FirstRanker.com ---
Augmented Limb LeadsE Goldberger
Precordial Leads
--- Content provided by FirstRanker.com ---
Frank Wison
Standard Limb Leads
--- Content provided by FirstRanker.com ---
-
+
--- Content provided by FirstRanker.com ---
Limb lead ILimb
- Lim
--- Content provided by FirstRanker.com ---
le
-
--- Content provided by FirstRanker.com ---
ba
le
--- Content provided by FirstRanker.com ---
d
a
--- Content provided by FirstRanker.com ---
I Id I
+
--- Content provided by FirstRanker.com ---
+
Einthoven's triangle
--- Content provided by FirstRanker.com ---
Einthoven's LawUnipolar Limb Leads
--- Content provided by FirstRanker.com ---
-+
VR
--- Content provided by FirstRanker.com ---
VL
VF
--- Content provided by FirstRanker.com ---
Augmented Limb LeadsaVR
+
--- Content provided by FirstRanker.com ---
Similarly, aVL and aVF
Augmented lead is 1.5 X unipolar lead
aVL = VL ? (VR + VF) /2
--- Content provided by FirstRanker.com ---
2 aVL = 2 VL ? (VR + VF)
VL + VR + VF = 0
--- Content provided by FirstRanker.com ---
VL = - ( VR + VF)2 aVL = 2VL + VL
aVL = 3/2 VL
--- Content provided by FirstRanker.com ---
Thank You