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109 terms

ekg study guide pt2

there are three parts
bi polar leads
Leads 1, 2, and 3 are known as the "standard limb leads" and are often referred to as?
lead 1
right arm (-) to left arm (+)
lead 2
Right arm -
Left leg +
lead 3
Left arm -
Left leg +
Augmented unipolar leads
leads Vr, VL, VF
Lead VR
RA + other limbs -
lead VL
left arm (LA) + others limbs negative
lead VF
LL + all other limbs -
unipolar precordial leads
V1, V2, V3, V4, V5, V6
lead v1
4th intercostal space, just to the right of the sternum
lead v2
4th intercostal space, just to the left of the sternum
lead v3
a line midway between V2 and V4
lead v4
left midclavicular line in the 5th intercostal space
lead v5
left anterior axillary line at the same level as V4
lead v6
left midaxillary line at the same level as V4
EKG paper
vertical axis records voltage, horizontal records time. normal is 25 mm per second, every heavy line equals 5mm
Horizontal axis
time, 1mm=.04sec / mm=.5sec
vertical axis
amplitude measured in milivolts, 1mm=.1mV
a graph that shows the amplitude as a function of time. shows positive and negative deflection.
A part of a line between two endpoints.
waveform plus segment
several wave forms
p wave
Atrial depolarization. normal does not exceed .11s in duration and 2.5 mm in height
QRS complex
Electrical impulse as it travels thru AV down to Purkinje fibers causing ventricles to contract. ventricular depolorization occurs from the endocardium to the myocardium to the epicardium.
Q wave
first negative deflection following the P wave
R wave
The First Positive Deflection After the Q Wave.
S wave
The downward or negative waveform that follows an R Wave, denotes the completion of ventricular depolarization.
T wave
repolarization of ventricle after S wave
U wave
This is a small wave, sometimes seen following the T-wave, and often when a patient has a potassium deficiency
deficient level of potassium in the blood
RR interval
interval between two R waves
if the ventricular rhythm is regular how do you find the heart rate?
the interval in seconds between 2 successive R waves divided in to 60 seconds= heart rate/min
if the RR interval is .2 seconds what is the heart rate per min?
60/.2= 300/min heart rate
if the ventricular rhythm is irregular how do you find the heart rate?
count the number of R waves in six seconds and multiply by ten.
if a irregular ventricular rhythm has 10 R waves within six seconds what is the rhythm.
6 x 10= 60/min(10x10)
PR interval
Time required for conduction from the SA node to AV node. The time between atrail and ventricular deplarization. This is normally 0.12 to 0.20 seconds.
QRS interval
represents time it takes for ventricular depolarization to occur / atrial repolarization is hidden / ventricular myocardial cells become positively charged / should not be more than .1 sec
PR segment
time delay artial--> ventricle propagation/filling. line from the end of the pwave to the onset of the Qrs complex.
J junction
point at which QRS complex ends and ST segment begins
ST segment
This represents the period between the contraction and the beginning of the recovery (or repolarization) of the ventricular muscles. from J point to the onset of the T wave
Somatic tremors, wandering baseline, 60 cycle interference, and broken recording
somatic tremors
Patients tremors or shaking the wires can produce jittery patterns on the EKG tracing.
Wandering baseline
sweat or lotion on th patients skin or tension on the electrode wires can interfere with the signal going to the EKG apparatus causing te baseline of the tracing to move up and down on the EKG paper.
60- cycle interference
can produce deflections occurring at rapid rate that may mimic atrial flutter. this is caused by electrical appliances or apparatus being used nearby while the tracing is taken.
broken recording
the stylus goes up and down trying to find the signal. tis can be caused by loose electrode or cables, or by frayed or broken wires
make sure the patient is laying on a comfortable bed or table large enough to support the entire body, good contact between skin and electrode, machine must be properly standardized: 1mV should produce deflection of !cm (10mm), patient and reading must be properly grounded to avoid alternating current interference, no electrical devices around the patient.
Stress testing
method for evaluation cardiovascular fitness, the patient is placed on a treadmill or a bicycle and then subjected to steadily increasing levels of work, an EKG and oxygen levels are taken while the patient exercises
indications for stress testing are?
evaluation of chest pain in patient with normal EKG, evaluation of patient who has recently had a myocardial infarction (heart attack), diagnosis and treatment of arrhythmias
some indications for stopping a stress test are?
patient develops chest pain, shortness of breath, or dizziness.
and blood pressure abnormalities
Exercise stress test
a study that evaluates cardiac function during physical stress by riding a bike or walking on a treadmill TILL 85 & OF HEART RATE IS REACHED OR CHANGES REQUIRE STOPPING THE TEST.
how do you find the target heart rate of a patient?
220 minus patients age.
Pharmacologic stress test
test for patients who cannot exercise vigorously by giving a vasodilator and tracking the symptoms. medications to make the heart rate rise instead of exercising , dobutamine, adenosine, persantine
Arrhythmias are due to the following
Arrhythmias of sinus origin, ectopic rhythms, conduction blocks, preexcitstion syndromes
Arrhythmias of sinus origin
when the electrical flow is to fast or to slow or irregular
normal sinus
60-100 bpm
sinus tachycardia
rhythm with a heart rate over 100 bpm
sinus bradycardia
rhythm with a heart rate less than 60 bpm
ectopic rhythms
when the electrical impulses orginate somewhere other than the Sinus node.
conduction blocks
impulses go down the normal track but encounters blocks and delays.
preexcitation syndromes
electrical impulses bypass the normal pathway and, instead goes down an accessory shortcut.
occurs when there is a decrease in the amount of blood flow to a section of the heart. usualy experienced as chest pain and discomfort and is called angina
myocardial infarction
the actual death of myocardial cells.
what wave indicates a MI on the EKG strip?
abnormal Q waves are the sign of MI, abnormal Q waves are >1mm(.04sec) wide and the height is greater than 25% of the R wave of that lead. Q wave combined with changes in T waves and ST seg, indiacate an acute MI
what is the world healt organiization criteria for diagnosis of an MI? At least two
clinical history of ischemic chest discomfort, changes in serial EKG tracings,rise and fall in srum cardiac markers
Ambulatory EKG monitoring
enables the evaluation of the patients heart rate, rhythm, and QRST morphology during the usual daily activities.
holter monitor (basic)
a portable electrocardiograph that is worn by an ambulatory patient to continuously monitor the heart rates and rhythms over a 24-hour period
the upper part of the breastbone
why use a holter monitor rather than a standard 12 lead EKG?
to rule out intermittent arrhythmias or ischemia that could be missed on a routine EKG.
what is the procedure of an holter monitor?
patient is hooked up to a holtor monitor and EKG sitgnales are recorded on a magnetic tape, after the time prescribed the patient returns to have it removed and the results anaylazed.
what is the typical electrode placement for holter monitoring?
-two electrodes are placed over bone near the v1
and v5.
-two indifferent electrodes placed over the manubrium
--one ground electrode placed over the 9th or 10 th rib at the right midaxillary line.
what is done before the ambulatory monitor is placed?
skin is prepped to place electrodes, EKG tracings are taken sitting, laying, and standing in order to be able to identify theses position changes
what is the diference between a positive holter and a negative one?
negative will have no significaqnt arrhythmias or ST changes.
what are somethings that can result in recording artifacts?
incomplete tape erasure, tape drag within the apparatus, battery depletion, loose connection , and movement of electrodes.
incomplete tape erasure
this can result in EKG tracings belonging to two different patients confounding both the scanner and the interpreter.
tap drag within the apparatus
this will result in recording of spuriously rapid cardiac rhythms. a narrowing of all EKG complexes and intervals should give a clue to this.
battery depletion
this may result in varying QRS amplitude
loose connection
can result in absence of all EKG signals which may mimic Bradycardia- tachycardia syndrome. clue to this artifact is the attenuated QRST morphology of the complexes beginning and ending the pause in Rhythm.
movement of electrodes-
may occur during scratching the chest near the electrodes and can produce tracings that look like malignant vetricular arrhythmias. underlting rhythm and rate remain undisturbed and should give a clue to this.
event monitoring
some symptoms are very infrequent that a holter monitor yields little useful data . tis is were an event recorder, a portable device that is used only when the patient is experiencing symptoms.
how does a event recorder work?
the ekg is recorded from the anterior of the chest wall on magnetic tape of a computer chip which is scanned later or is can be transmitted telephone to a receiving station for immediate attention.
should be given to all patients with acute chest pain that mat be due to cardiac ischemia, suspected hypoxemia of any cause, and cardiopulmonary arrest. prompt treatment of the hypoxemia
may prevent cardiac arrest. for patients breathing spontaneously, masks and nasal cannulas can be used.
An abnormally low concentration of oxygen in the blood, Cyanosis (Skin appearing bluish due to insufficient oxygen)
Cheyne-Stokes respiration (irregular pattern of breathing)
Increased blood pressure
Apnea (temporary cessation of breathing)
Tachycardia (increased rate of heartbeats, more than 100 per min)
Hypotension (abnormally low blood pressure, below 100 diastolic and 40 systolic. Here, as an effect of an initial increase in cardiac output and rapid decrease later.)
Ventricular fibrillation (irregular and uncoordinated contractions of the ventricles)
Asystole (severe form of cardiac arrest, heart stops beating)
Polycythemia (abnormal increase in RBCs. The bone marrow may be stimulated to produce excessive RBCs in case of patients suffering from chronic hypoxemia)
cardiopulmonary arrest
asystole: absence of systole; failure of the ventricles of the heart to contract (usually caused by ventricular fibrillation) with consequent absence of the heart beat leading to oxygen lack and eventually to death.
adrenaline; activates a sympathetic nervous system by making the heart beat faster, stopping digestion, enlarging pupils, sending sugar into the bloodstream, preparing a blood clot faster. management of cardiac arrest. successful defibrillation is enhanced by Administration of epineprine and proper oxygenation.
isoproterenol (isuprel)
produces an overall increase in heart rate and myocardial contractility,, but newer agents have replaced it in most clinical settings. it is contraindicated in the routine treatment of cardiac arrest.
for significant Hypotension in the absence of hypovolemia. hypotention is when systolic bp is less than 90mmhg with evidence of poor tissue perfusion , oliguria or changes in mental status. should be used at the lowest dose that produces adequate perfusion
A decreased volume of circulating blood in the body.
occurs when blood pressure during and after each heartbeat is much lower than usual. This means the heart, brain, and other parts of the body do not get enough blood
pumping a liquid into an organ or tissue (especially by way of blood vessels)
beta blockers include?
Propranolol,metoptolol,atenolol, and esmolol (olol)
Beta blockers
reduce heart rate, BP, myocardial contractility, and myocardial oxygen consumption makeing them effective in the treatment of angina pectoris and hypertention
angina pectoris
a heart condition marked by paroxysms of chest pain due to reduced oxygen to the heart
A sudden recurrence or attack of a disease; a sudden worsening of symptoms.
drug of choice for the suppression of ventricular ectopy , including ventricular tachycardia and flutter.excessive doses can produce neurological changes, myocardial depression, and circulatory depression.neurological toxicity iS manifested as drowsiness , disorientation, decreased hearing ability, paresthesia, and muscle twitching, and eventual seizures.
ventricular ectopy
A ventricular ectopic beat (VEB) is an extra heart-beat originating in the lower chamber of the heart. This beat, also called a premature ventricular contraction (PVC), occurs before the beat triggered by the heart's normal function
ventricular tachycardia
Ventricular tachycardia (V-tach or VT) is a tachycardia, or fast heart rhythm, that originates in one of the ventricles of the heart. This is a potentially life-threatening arrhythmia because it may lead to ventricular fibrillation, asystole, and sudden death.
ventricular fibrillation
fibrillation of heart muscles resulting in interference with rhythmic contractions of the ventricles and possibly leading to cardiac arrest.
absence of systole; failure of the ventricles of the heart to contract (usually caused by ventricular fibrillation) with consequent absence of the heart beat leading to oxygen lack and eventually to death.
An abnormal sensation, typically tingling or pricking ("pins and needles"), caused chiefly by pressure on or damage to peripheral nerves
used in the treatment of (PSVT) paroxysmal supraventricular tachycardia, terminated 90% of PSVT episodes in adults and infants. also used for slowing down ventricular response to atrial flutter and fibrillation, monitoring is advised due to hypotension that could occur.
Paroxysmal supraventricular tachycardia( PSVT)
A common type of heart arrhythmia. Sudden bursts of very fast, or racing, heart rhythm. PSVT is more common in women than men. Symptoms include faintness, dizziness, anxiety and chest discomfort. PSVT is diagnosed with a loop recorder, which is worn 24 hours a day
Atrial flutter
cardiac arrhythmia where atrial contractions are rapid but regular, p waves have saw toothed pattern ,an abnormal heart rhythm that occurs in the atria of the heart. When it first occurs, it is usually associated with a fast heart rate or tachycardia (230-380 beats per minute), and falls into the category of supra-ventricular tachycardias.
Atrial fibrilation
An abnormal rhythm or heartbeat pattern involving the atria or upper chambers of the heart. It can interrupt the normal flow of blood through the heart, allowing clots to form. These clots can potentially travel through the arteries, lodge in the brain and cause strokes.
abnormally small production of urine; can be a symptom of kidney disease or obstruction of the urinary tract or edema or an imbalance of fluids and electrolytes in the body
increases the force of cardiac contraction as well as cardiac output, toxicity is up to 20% common, monitoring is required for symptoms such as : yellow vision, nausea, vomiting , and drowsiness.
Morphine sulfate
drug of choice for pain and anxiety associated with acute MI . in high doses morphine sulphate may cause respiratory depression. it is a controlled substance and has a tendancy for abuse and addiction
powerful smooth muscle relaxant effective in relieving angina pectoris. it is effective for both extertional and rest angina
rest angina
Angina at rest more commonly indicates that a coronary artery has narrowed to such a critical degree that the heart is not receiving enough oxygen even at rest. Angina at rest infrequently may be due to spasm of a coronary artery (a condition called Prinzmetal's or variant angina). Unlike a heart attack, there is no permanent muscle damage with either exertional or rest angina.
extertional angina
Exertional angina usually feels like a pressure, heaviness, squeezing, or aching across the chest. This pain may travel to the neck, jaw, arms, back, or even the teeth, and may be accompanied by shortness of breath, nausea, or a cold sweat. Exertional angina typically lasts from one to 15 minutes and is relieved by rest or by taking nitroglycerin by placing a tablet under the tongue.