EKG Flashcards
What is an EKG?
An electrocardiogram (ECG or EKG) is a recording of the electrical activity of the heart over time produced by an electrocardiograph, usually in a noninvasive recording via skin electrodes.
EKG word origin
electro, because it is related to electrical activity
cardio, Greek for heart, (German Kardio)
gram, a Greek root meaning “to write”.
5 components of basic EKG
RATE RHYTHM HYPERTROPHY INFARCTION AXIS
Rate is it what or what?
bradycardia or tachycardia
What sets the rate at which the heart beats?
SA Node - Sinus Rhythm NORMAL SINUS Rhythm
Right Ventricular Hypertrophy -
large R wave in V1
Left Ventricular Hypertrophy -
S in V1 and R in V5 > 35 mm
ST segment elevation
- means acute or recent
ST segment depression >
2mm older injury, ischemia
Axis – refers to
the diection of depolarization wave
What is an EKG Used for?
The display indicates the overall rhythm of the heart and weaknesses in different parts of the heart muscle.
What is the best way to measure and diagnose abnormal rhythms of the heart?
The best way to measure and diagnose abnormal rhythms of the heart through EKG
particularly abnormal rhythms caused by
damage to the conductive tissue that carries electrical signals
abnormal rhythms caused by levels of
dissolved salts (electrolytes), such as potassium, that are too high or low.
In myocardial infarction (MI), the EKG can identify
damaged heart muscle.
What can’t the EKG do?
It can only identify damage to muscle in certain areas, so it can’t rule out damage in other areas.
The ECG cannot reliably measure
the pumping ability of the heart.
Since an ECG cannot reliably measure pumping ability of the heart, what should be used?
ultrasound-based (echocardiography)
nuclear medicine tests
The electrical impulse starts in the _____ ______and moves through _____ to the ______ _______
It then moves through the left bundle branch (LBB) and right bundle branch (RBB) and finally to the purkinje fibers to contract the ventricles.
SA node
the atria to the AV node.
Bachman’s bundle electrically connects
the left and right atria.
There is a pause at the __ _____ when? the _____ the ____ __ ___
AV node before the signal hits the Bundle of His (pronounced hiss).
How many electrode placed on the body and where? What are those leads called?
10 electrodes placed on the body . . . Yet called a 12 lead?
3 limb leads (I, II, III) 3 augmented limb leads (aVR, aVL, aVF) 6 chest leads \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 12 leads
Why is it called 12 lead when their are only 10 leads?
*The EKG machine does the work to “create” the other leads, you just put the 10 stickers on.
What is a lead?
a combination of electrodes that form an imaginary line in the body along which the electrical signals are measured.
Frontal Plane View
Leads I, II, III \+ Augmented limb leads aVR, aVL, aVF \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Frontal plane view of the heart
Sensing the heart’s electrical activity
via electrodes (contacts placed on the surface of the body )
For EKG, anatomical orientation is from the
subject’s perspective
right = left
The basic four limb electrodes:
electrical polarity:
neutral or ground
negative
positive
(manipulated by the EKG machine)
polarity
Lead I goes
toward left arm
Lead II goes
toward left foot
Lead III goes
(down & rightward)
Leads I, II, & III together create what
“Einthoven’s triangle”
“Einthoven’s triangle” is what kind of triangle whose vertices lie to
an equilateral triangle whose vertices lie at the left and right shoulders and the pubic region and whose center corresponds to the vector sum of all electric activity occurring in the heart at any given moment, allowing for the determination of the electrical axis.
Einthoven’s triangle is approximated by the
triangle formed by the axes of the bipolar electrocardiographic (ECG) limb leads I, II, and III.
The center of the Einthovens’s triangle offers
a reference point for the unipolar ECG leads.
Plus “augmented” leads, e.g.
aVR (augmented vector right)
Plus “augmented” leads, e.g.
aVL (augmented vector left
Plus “augmented” leads, e.g.
aVF (augmented vector foot)
Chest leads
V1 - V6
provides cross sectional view of the heart
horizontal plane
Limb leads
I, II, III
aVR, aVF, and aVL
Limb Lead I
I, from the right arm (-) toward the left arm (+)
II, from the right arm toward the left leg
Limb Lead II
LIMB LEAD III
III, from the left arm toward the left leg
aVR,
augmented lead toward the right (arm)
aVL,
augmented lead toward the left (arm)
aVF,
augmented lead toward the foot
aVR is approx opposite of
of I and should essentially mirror the shape of I vertically