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Electrical Flowof the Heart
NRSG450 Module Two
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Background of Electrical Flow of the Heart
• The flowing electricity is summarized to give a general direction. This is called the vortex.
• The vortex is the electrical direction viewed on the monitor.
• Electrical flow toward a positive electrode gives a upward deflection. Flow away from the positive electrode gives a downward deflection.
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Lead II
+
-
Background of Electrical Flow of the Heart
• The electrical activity of the heart is examined from several different views or directions, commonly called leads.
• The common leads are six limb leads and six chest leads. Many more leads are possible and are used in special situations.
• Most patients with a non-cardiac condition are monitored in Lead II.
• Cardiac patient monitoring is based on the expected problems, usually MCL1 &/ MCL 5/6
Reading Electrical Flow of the Heart• 12 Lead EKG
I
IIII
III
AVR
AVL
AVF
VI or MCLI
V2 or MCL2
V3 or MCL3
V4 or MCL4
V5 or MCL5
V6 or MCL6
Lead II monitoring strip
Reading the Electric Flow of the Heart
The EKG Rhythm Strip
• A straight line is called the isoelectric line. It is seen when no electrical flow is detected in the heart.
Reading the Electrical Flow of the Heart
Reading the Electrical Flow of the Heart
The electrical activity of the heart is picked up be electrodes, travels through the wires to a heated stylus and transferred to specially designed EKG paper.
Reading the Electrical Flow of the Heart
• EKG is recorded on graph paper traveling at 25mm per second
• The horizontal axis is time.– 1 small block=1mm=0.04 sec– 5 small blocks= 1 big block =
5mm = 0.2 sec– 5 big blocks = 1 second– 30 big blocks = 6 seconds
• The vertical axis is voltage.– 1 small block = .01 mv– 10 small blocks=2 big blocks = 1
mv
Reading the Electrical Flow of the Heart
• One heart beat or an electrical wave propagation
Depolarization wave
Heart muscle contraction
Reading the Electrical Flow of the Heart
San
San Diego Paramedics
Reading the Electrical Flow of the Heart
DRAG LABELS TO CORRECT LOCATION AND REBUILD
THE CHART
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Anchoring the Information• Label the waves.
p
p
p
p
p
p
p
p p
p
p p
p
p
p
qrs qrs
qrs qrs
qrs qrs
qrs qrs
qrs
qrs
qrs
qrs
T
T T
TT
T T
T
T
T
T
T
pr
pr = 0.44
pr = 0.20
= 0.12
QRS = .06
QRS = o.o4
QRS = o.o6
DRAG LABELS TO CORRECT LOCATION AND REBUILD
THE CHART
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Reading the Electrical Flow of the Heart
• p wave = atrial depolarization• Accounts for the time electrical
stimulation moves across the atria.
• Duration 0.06 – 0.12 sec (2 small blocks> 4 small blocks)
• Located before QRS complex• Height 2-3 mm (0.2-0.3 mv)• Shape rounded & positive
(upright)
Suran Dutsan@ rutgers.edu
Reading the Electrical Flow of the Heart
• PR interval involves the atrial and nodal depolarization
• Measure from beginning of p wave to the beginning of the QRS
• Duration 0.12 – 0.20 sec
Reading the Electrical Flow of the Heart
• Ventricular depolarization is represented by the QRS complex
location
Location follows the PR interval.Duration 0.06 - 0.12 secondsAmplitude dependent on Lead (~5-30 mm)Configuration dependent on Lead Deflection usually a combination of negative and positive, varies with leads
Schwimmin
Reading the Electrical Flow of the Heart
• ST segment from the end of the S wave to the beginning of T wave
• Usually isoelectric, • May be from -0.5 - +1 mm
from the isoelectric line
Reading the Electrical Flow of the Heart
• T wave is ventricular repolarization
Location follows the s waveConfiguration is round & smooth (looks like a big p wave)Deflection is usually positive
Reading the Electrical Flow of the Heart
• QT segment is measured from the beginning of the QRS complex to the end of the T wave.
• Duration is rate dependent
• Not routinely measured
Reading theElectrical Flow of the Heart
www.overboro.kctc.edu
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