electrocardiogram
EKG or ECG; procedure frequently used in diagnosis of heart disease and dysfunction
What can an EKG detect?
cardiac arrhythmia or dysrhythmia, ischemia, electrolyte imbalance, effects of cardiac medications, damage caused by an MI
What is the electrical pathway of the heart's conduction system?
SA node->AV node->Bundle of His->Right and Left Bundle Branches->Purkinje fibers
atria contract
When the SA node is stimulated, what mechanical action happens in the heart?
What has to happen for the ventricles to contract?
Electrical conduction has to pass through the AV node, down the Bundle of His, through the right and left bundle branches, into the purkinje fibers. Once they reach the Purkinje fibers, then the ventricles will contract.
What is the purpose of the gel on the electrodes?
increase conductivity to read the heart's electricity and to amplify the waveforms
Single channel and multichannel
2 types of EKG machines
12 different points of view or angles on ekg
An EKG shows _________ of the heart
10
How many electrodes are used to perform an EKG?
What is unique about EKG paper?
It is head-sensitive and pressure-sensitive.
1mm x 1 mm
What size is a small block on EKG paper?
5mm x 5 mm
What size is a large block on EKG paper?5mm x 5 mm
Why would a CMA increase the speed of the EKG paper?
If the heart rate were very fast, the speed would be increased to 50mm per second.
0.04 seconds
How much time does each small square on EKG paper represent?
0.2 seconds
How much time does each large square on EKG paper represent?
12 different points of view or angles on ekg
What is another name for amplitude? how tall the tracing is. It is represented by 1x, 2x, or 3x.
standardization mark; 2 large boxes or 10 small boxes
How big is the normal amplitude/gain on an EKG? Upside down U or a rectangle with the bottom out of it; 2mm wide and 10 mm high
it is the process of making sure that an EKG on one machine will compare to the EKG on another machine.
What is the purpose of standardization?
Limb leads
What are the leads RA, LA, RL, LL collectively called?
rhythm strip
A 6 second strip in Lead II is called a
Lead II
Which lead (view) is a rhythm strip usually taken in?; electrical connection between RA & LL
Right leg
Which lead (wire) is always the ground?
AVR, AVF, AVL
Which 3 leads (views) are the augmented leads?
V1, V2, V3, V4, V5, V6
Which leads (views) are the chest, Precordial or Vector leads?
It is a non-invasive test that won't hurt, have to lie still, clothing should be removed from the waist up, no jewelry, gown open in the front. Any lotion needs to be removed with alcohol pads. Empty their bladder 10 minutes prior to the exam.
What education should you give to your patient before starting the EKG?
supine position, arms at the sides, or semi-fowlers
How should the patient be positioned when performing an EKG?
Where is V1 placed?
4th intercostal space on the right sternum
Where is V2 placed?
4th intercostal space on the left sternum
Where is V3 placed?
Between V2 and V4, 5th intercostal space
Where is V4 placed?
Mid-clavicular line on the left side, 5th intercostal space
Where is V5 placed?
Between V4 and V6, anterior axillary left side
Where is V6 placed?
Mid-axillary line on the left side, 5th intercostal space
V1, V2, V4, V3, V6, V5
What order do you place the chest leads?
Ventricular repolarization (ventricular relaxation)
What does the T wave represent?
ischemia or injury to the heart muscle
An elevation or depression of the ST segment can indicate; lack of blood supply; insufficient oxygenation of tissue
normal sinus rhythm
What is the "normal" heart rhythm?
Na+
Depolarization is caused by the influx what main ion
0, 1
Depolarization is occurs during which phase
4
Slow depolarization occurs during what phase moderated by leaking sodium ion channels and balanced by potassium efflux
3
Repolarization occurs during what phase
5
How many large squares on an EKG printout makes up a second
300
To get heart rate, you must divide this number by the number of large squares
1,500
To get heart rate, you must divide this number by the number of small squares
Ca++
The SA node is dependent on what type of ion influx
K+
Repolarization is caused by the efflux of _______ ion
wave
movement away from line upward (positive) downward (negative)
interval
waveforem plus a segment
midclavicular
middle of clavicle
midaxillary
middle of axillary (armpit)
depolarization
when electrical system stimulates myocardial cells that results in contraction of the stimulated heart muscle
complex
several waveforms
electrode
a specialized interface between the hman body and an EKG machine; sticky skin sensors that attach to the patient
lead
flexible conductors connected to or leading our from an electrical device and placed on the skin to measure eletrical impulses
PQRST waves
standard waveforms found on the EKG tracing. Each wave corresponds to a specific event within the heart's electrical cycle
intercostal
between the ribs
P wave
atrias contract; polarization; What wave represents atrial depolarization?; which part of the EKG complex is formed when the atria contract?; the first impulse recorded on the ECG paper from the atrial contraction is known as the _______
T wave
heart rests; repolarization; during the recovery of the ventricles, the ______ is produced; What wave represents ventricle repolarization; is after QRS and represents repolarization of the ventricles (time of recovery before another contraction)
negative deflection
a wave that exists below the isoelectric line
positive deflection
a wave that exists above the isoelectric line
EKG performed
__________ is used to detect damage from previous heat attacks, detect enlargement of heart muscles,disturbances in rhythm and other abnormal conditions, cardiac baseline.
Electrocardiogram machines
____________ are multichannel, computerized, digital computer-based, ot single-channel and produce an electrocardiograph.
multichannel EKG machine
12 lead instrument, record the electrical activity of the heart stimultanelusly from 12 views
digital computer-based multichannel EKG machine
simultaneous 12-lead interpretive analysis; data is printed out and also stored in memory; tracing is done is about 1 minute on a single 8" x 10" ECG paper; most commonly used; can quickly show up on a computer are lightweight so they can be easily moved
single-channel
older model; run one lead at a time; EKG strips that require mounting
baseline of an EKG
isoelectric line; it is the flat line that separates the various waves represents the periods in cardiac cycle where there is no currents
atrial depolarization
when atria contracts this begins the cardiac cycle; it is recorded as P wave on the graph paper;impulse goes to AV node->bundle of His-> spreads to Purkinje fibers which contract ventircles and produce QRS complex on the graph; What does the P wave repres
40-45; then every 5-10 years after baseline reading
Recommended age to establish base reading for EKG
thermal stylus
imprints electrical activity on the EKG paper on non-digital EKG
records voltage
vertical axis of paper
measures time
horizontal axis of paper
paper moves through the machine at a rate of
25mm/sec; small square= 1mm x 1mm and represent 0.04 seconds, large square=5mm x 5mm and represent 0.2 seconds; it will move over 5 squares in 1.0 sec.
Leads I, II, III (limb leads)
standard or bipolar leads; monitor two electrodes; placed on limb electrodes on fleshy part of upper outer arms and inner lower calves; Which 3 leads (views) make up Einthoven's Triange?
Lead I
records electrical voltage difference between right and left arm
Lead III
records voltage difference between left arm and left leg
augmented limb leads AVR, AVL, AVF
are also known as standard or bipolar are the next 3 in a 12 lead EKG
Conduction of heart
SA node-->AV node-->bundle of His-->right and left bundle branches--> purkinje fibers
cardiac cycle
P wave (atrial depolarization/ contraction->systole) QPR complex (ventricle depolarization/ contraction<-systole), T wave (ventricle repolarization. recovery-> diastole)
Red/Green leads (christmas on bottom)
calf leads; RED=Left, Green= Right
Black/white leads (top)
top limbs; Black=Left, White= Right
12
the routine EKG consists of ____ leads
relaxed
The patient must be _________ for a good tracing to be obtained.
mild detergent/scouring powder
metal electrodes should be cleaned with __________
electrolyte
A proper amount of _____ must be used with each metal electrode to provide maximum electrical conduction.
EKG standardization
the ______ of the EKG is necessary to enable a physician to judge deviations from the standard; provides a reliable reading; enables provider to judge deviation from the standard
2mm wide and 10mm high
the usual standardization mark is _____ in size.
EKG sensitivity
if the tracing is too large, the ____ button should be turned down to one half.
25
the tracing paper is normally run at a speed of ______ mm/second.
electrical impulses/activity
all muscle movement produces ______
EKG amplifier
the current enters the electrocardiograph through the wires to reach the ________; Magnifies the heart's electrical signal so it can be recorded.
enlarges
the amplifier _______ the electrical impulses
QRS complex
when the muscles of the ventricles contract, the _______ of waves is produced on the EKG paper; ventricles contract; polarization; What wave represents Ventricle depolarization; What wave represents Atrial repolarization
augmented
means to make larger
precordial
Chest leads are also called ______ leads
alternating current
AC or ______ current interference is caused by additional electrical activity.
AV node
In the electrical conduction system, the first area of the heart to receive the electrical impulse is the ______.; atrioventricular node; regulates impulses bewteen atria and ventricles
aVR
recording of the hearts voltage difference between the right arm electrode and the central point between the left arm and the left leg.
sinus, right
the impulse routinely begins in the ________ of the ____ atrium
The mounting of the EKG will depend on_____
the machine used to record the tracing
multiple-lead EKG
EKG strips that are already mounted
EKG 1/2 standard
if the tracing is loo large, the sensitivity button should be turned down to_____
electrical impulses of the heart
What does EKG measure?
Leads I, II, III
standard or bipolar leads
Purkinje fibers
carries the electrical impulse across the heart and causes the ventricles to contract; fibers that causes muscles of the ventricle to contract; fibers that serve to conduct electrical impulses through the right and left ventricles
50 mm/sec
if the EKG cycles are too close together, the speed should be changed to_____
length of wave
interval
segment
portion of EKG between two waves; line between two waveforms
impulse
momentary surge of current
voltage
difference in electrical potential
galvanometer
changes impulses into mechanical motion; fibers that causes muscles of the ventricle to contract
temperature of stylus
_____ can be adjusted to control the thickness of line
repolarization
reestablishment of a polarized state in a muscle or nerve fiber following contraction or conduction of a nerve impulse; period when heart momentarily relaxes; the resting state of the myocardial wall when there is not electrical activity in the heart
SA node, pacemaker
sinoatrial node; originates impulses that stimulate the heartbeat; an electrical impulse originates in the modified myocardial tissue in the ______;the impulse generator is called the _____ or _____; this impulse generator is called the pacemaker or _____