ELECTROCARDIOGRAPHY Flashcards
He demonstrated the direct contact with the electrical
generator or ground on electrical conductor could lead to a
muscle contraction in a frog leg.
Luigi Aloisio Galvani in 1786
They confirmed that an electrical current accompanies each
heart beat by applying a galvanometer to the base and
apex of an exposed ventricle.
Rudolph von Koelliker and Heinrich Muller in 1856
realizes that
electricity is associated with the heartbeat.
Carlo Matteucci in 1842
analyzes the electric pattern
of frog’s heart.
* He used the electrometer to record the
electrical activity of the exposed frog hear
marey
, credited for the invention of
EKG
* Developed the elegant, reliable and
sensitive string galvanometer. He was able
to record electrical forces of the heart from
the hands and feet of the subject without
even addressing death.
William Einthoven
non-invasive diagnostic test that evaluates your
heart’s electrical system to assess for heart disease.
electrocardiogram or ecg
Converts the heart’s electrical activity into lines called
waveforms
contraction of any muscle is
associated with electrical changes called
depolarization
Einthoven name the wave form produce by hearts electrical
system
P, Q, R, S, T
considered the pacemaker of the heart.
* The conductivity of the heart, normally follows an electrical
pathway
SA node
rapid heart rate
tachycardia
slow heart rate
bradycardia
irregular heart rate
Arrhythmia
REASONS WHY ECG IS DONE
If the patient had heart disease in the past.
* If the patient has a medical condition that predisposes to
heart disease, such as hypertension, diabetes, high
cholesterol, or inflammatory disease.
* If the patient has other significant risk factors for cardiac
disease.
INDICATIONS
heart arrhythmias
Myocardial infarction (heart attack)
Coronary artery disease (CAD)
congenital heart defects (CHD)
Are applied at specific locations on the patient’s chest
wall and extremities to view the heart’s electrical
activity from different angles and planes
electrodes
graph paper used to measure rates of impulse
formation and the duration of the electrical events that
occur in the heart
ecg paper
Each Small box is equal to
0.04 seconds of time
Each large box is equal to
0.20 seconds of time
ECG recorder compares the electrical activity detected in
different electrodes. The electrical picture is called
LEAD
The ECG is made up of 12 characteristic views of the heart
o 6 from limb leads
o 6 from chest leads
Electrode positioned in the 4th intercostal space in
the right sternal border
V1
4th ICS in the left sternal border
V2
Midway between V2 and V4
V3
5th ICS in the left midclavicular line
V4
Same level as V4, anterior axillary line
V5
Same level as V4 and V5, midaxillary line
V6
represents atrial contraction
o The shape of it remains the same unless it is
degenerated from different focus.
P wave
represents ventricular depolarization composed of 3
waves
QRS wave
is the first negative deflection
Q wave
is the first positive deflection after the P
wave
R wave
is the negative deflection following R
wave
S wave
Normal duration of QRS complex. represented by three small
squares
0.08 to 0.12 seconds
Measured from the beginning of P wave to the
beginning of QRS complex
PR Interval
The normal PR interval is ______. represented
by 3-5 small squares.
0.12 to 0.2 sec
an isoelectric line representing early ventricular
repolarization
ST segment
represents ventricular repolarization
o usually positive, rounded and slightly asymmetric
T test
results from slow repolarization of ventricular Purkinje
fibers
o more common in lead V3
U wave
represents total time required for ventricular
depolarization & repolarization
o from the beginning of QRS complex to the end of T
wave
QT interval
normal QT interval is
0.36 to 0.45 seconds
