175 terms

ProfessionalEducation.Group - EKG

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Automaticity
the ability to spontaneously generate and discharge an electrical impulse
Excitability
ability to respond to an electrical impulse
Conductivity
transmit an electrical impulse from one cell to another
Contractility
ability of myocardial cells to shorten and lengthen its muscle fibers
Extensibility
the ability of the cells to stretch
P wave
atrial depolarization
QRS complex
ventricular depolarization
Q wave
first downward deflection in QRS
R wave
first upward wave of QRS
S wave
any downward wave preceded by an upward wave
QS
if no upward wave occurs before a downward wave, that downward wave is referred to as
ST segment
horizontal segment of baseline following the QRS complex; NO WAVE
ST segment
represents initial phase of ventricular repolarization, although the actual amount of repolarization in this phase is small
Depolarization
contraction
Repolarization
rest
T wave
ventricular repolarization
QT interval
ventricular systole
5 squares
how many 1mm squares are between each heavy black line (large boxes)
.04 seconds
how much time each 1mm square represents
.2 seconds
how much time is between the two heavy black lines (5mm large box)
Sinus Rhythms
- normal appearing P wave
- PR interval will measure in the "normal range" of 0.12-0.20 second
- QRS typically will measure in the "normal range" of 0.06-0.10 second
Sinus Rhythm
- normal rhythm
- main attribute is regularity
- hr = 60-100
Sinus Bradycardia
- hr <60 bpm
- all other steps in this strip are normal
Sinus Tachycardia
- hr >100bpm
- complexes come closer together; this can result in the P wave becoming partially buried within the T wave
Sinus Arrhythmia
- normal but extremely minimal increase in heart rate
- closely resembles normal sinus rhythm with the only distinction being the intervals from one cardiac complex
Sinus Arrest
- sudden absence of electrical activity
- pause
- R to R intervals will be constant prior to and following the pause
Atrial Rhythms
- the dysrhythmias in this category occur as a result of problems in the atria
- primarily effect the p wave
Premature Atrial Complex
- frequently occur in bradycardic rhythm
- occurs when the electrical impulse occurs from a location in atria other than the SA node
- P wave is changed; they will be upright but have biphasic or other irregularities
Wandering Atrial Pacemaker
- at least three different shaped P waves
- no other changes may be observed
- rhythm may or may not be regular
- PR interval may be effected
Multifocal Atrial Tachycardia
- faster version of wandering atrial pacemaker
- at least three different shared P waves
- seen in COPD pts
Atrial Flutter
- obstruction w/in atrial electrical conduction
- a series of rapid depolarizations occur two, three, four, or more times per QRS complex
- there are no P waves, they become F waves, each flutter wave represents atrial depolarization
- Saw Tooth Pattern
Atrial Fibrillation
- occurs when multiple electrical impulses occur within the atria
- chaotic electrical activity results in a choatic wave form between the QRS complexes
- p waves are absent they are replaced by small f wavves
- random electrical activity
course f waves
majority measure 3mm or more
fine f wave
majority of waveforms measure less than 3mm
Ventricular Rhythms
- dysrhythmias occuring because of failure of pacemakers w/in the heart or abnormal locus of stimulation within the ventricle
- each rhythm in this category will share unique morphologic features which separate them from other rhythms
- other than Asystole and V.Fib which are unique, the remaining rhythms typically present without P waves, and will display wide, bizarre QRS complexes
Rate = 0
Ventricular Asystole Rate
Rate <20bpm
Ventricular Rhythm : Agonal Rate
Rate 20-40bpm
Idoventricular Rate
Rate 40-100bpm
Accelerated Idioventricular Rate
Rate >100bpm
Ventricular Tachycardia Rate
Rate : electrical chaos
Ventricular Fibrillation Rate
Premature Ventricular Complexes
- frequently occur in bradycardic rhythms
- occur when an early electrical impulse occurs from a location in either ventricle
- absence of P waves
- bizarre QRS complex
Agonal Rhythm
- HR <20bpm
- no p waves
- wide and bizarre QRS complex
Idioventricular Rhythm
- HR 20-40bpm
- no p wave
- wide and bizarre QRS complex
P wave
QRS complex
ST segment
T wave
Accelerated Idioventricular Rhythm
- HR 40-100bpm
- no p wave
- wide and bizarre QRS complex
- abnormally wide range
Ventricular Tachycardia
- HR >100bpm
- no p wave
- wide and bizarre QRS
- 50% of pt will be unconscious; some will be treated w/ defibrillator
- pulseless; can lead to V.Fib
Ventricular Fibrillation
- no p wave
- no QRS complexes
- chaotic wave form
- no measurable rate
- heart is not actually beating; chaos occurs as a result of small regions of tissue which are independently depolarizing
3mm of greater
course v.fib waves
3mm or less
fine v.fib waves
Asystole
- occurs when there is a total absence of electrical activity in the heart
- patient is clinically dead
- absence of P waves and QRS complexes
Ventricular Asystole
- asystole but with p waves
- patient is clinically dead
Heart Block Dysrhythmias
- these dysrhythmias occur for a variety of reasons
- may be congenital as is the case in First Degree Heart Block
- they may be secondary to medications or the result of transient illness or disease which results in tissue death occurring to a portion of the conduction system
First Degree Heart Block
- looks like sinus rhythm but has a long PR interval
- PR interval >0.2s
- rate, regularity, P wave morphology, and QRS duration and morphology will be unaffected
- prolonged PR with NO QRS DROP
Second Degree Heart Block Type I
- aka Wenckebach
- typically stable
- progressiveley prolonged PR interval WITH QRS DROP
- unique feature is presence of a prolonging PR interval from one cardiac complex to the next until it reaches a point where the QRS complex is blocked or missing
- p-p intervals are regular and r-r intervals are irregular
Second Degree Heart Block Type II
QRS complexes occurring in a specific pattern in a ratio w/ P waves (2:1 or 3:1)
Second Degree Heart Block Type II
QRS complexes that occur in a more unstable, unpredictable manner
Third Degree or Complete Heart Block
- result of dz or tissue death; blockage preventing electrical impulses within the atria from entering the ventricular conduction system
- outcome of this impediment are two independently functioning pacemakers within the heart; essentially, the atria and ventricles are electrically dissociated from one another
- regularly occurring P waves and QRS complexes but two distinctly differed rates
P wave
SA node
PR interval
AV node, bundle of His, Bundle Branches, Purkinje fibers
P wave
ventricular diastole
PR interval
ventricular filling/diastole
QRS complex
ventricular systole
T wave
ventricular diastole
5
how many large boxes = 1 second
1 second
5 large boxes
1mm (small box)
0.04 seconds
5mm (large box)
0.20 seconds
5 large boxes
1 second
6 seconds
how many seconds are in one rhythm strip
.12-.20 seconds (3-5 boxes)
normal PR interval length
atrial enlargement
Prolonged P wave
heart block
prolonged PR
AVR lead
P wave is inverted and lead is useless
myocardial infarction
large q wave
hypercalcemia
shortening of QT
hypocalcemia
lengthening of QT
rhythm comes from ventricles
wide/prolonged QRS
rhythm comes from atria
narrow/short QRS
deviation from baseline in the ST segment
- ischemia/infarction
- pericarditis
- electrolyte abnormality
- ventricular strain
lives under the T wave
potassium
ischemia
inverted T wave
Atrial Enlargement
- biphasic P wave on ECG
- looks like an S
- lead V1 is best for seeing this
Lead V1
best lead for seeing atrial enlargement
Ventricular Hypertrophy
- thick wall dilation; CHF
- thin wall dilation; cardiomyopathies
- v1 to v4
Leads V1 to V4
leads best used for seeing ventricular hypertrophy
Right Atrial Enlargement
- Diphasic p wave (S shape)
- initial part is longer
Left Atrial Enlargement
- Diphasic p wave (S shape)
- terminal part is longer
- can be caused by mitral stenosis
Right Ventricular Hypertrophy
R wave progressively smaller from V1 to V4
Left Ventricular Hypertrophy
- large negative S in V1
- Large Positive R in V5
OR
sum of the S(s) in V1 and R in V5 is greater than 7 boxes
Inferior
area of infarction involving
- right coronary artery
- left circumflex artery
Posterior
area of infarction involving
- proximal right coronary artery
- left circumflex artery
Anterior
area of infarction involving
- left anterior descending artery
Lateral
area of infarction involving
- left circumflex artery
Right ventricular
area of infarction involving
- proximal right coronary artery
Inferior
area of infarction associated with
- Leads II, III, and aVF
Inferior Infarction, Anterior Infarction, Lateral Infarction
ST elevations
Posterior
area of infarction associated with
- Leads V1, V2, V3
Posterior Infarction
- ST depression
- large R wave
Anterior
area of infarction associated with
- Leads V1, V2, V3, V4
Lateral
area of infarction associated with
- Leads V1, AVL, V5, V6
Right ventricular
area of infarction associated with
- elevations in leads II, III, aVF, and V1
Right ventricular infarction
large R wave V4
Lead 1
most useful lead when looking at electrical activity right arm to left arm
Lead 2
-connects right arm to the left foot and goes downward and to the left
- follows direction of the heart best/best for arrhythmias
Lead AVF
what lead is created by connecting the two arms together to create an "average"
Lead AVF
correlates most strongly to the electrical activity that is moving straight up or down
Lead AVL
what lead is created by connecting the right arm and leg together then comparing this average electrode to the left arm electrode
Right Axis Deviation
- Lead 1 = negative QRS
- AVF = positive QRS
Normal Axis
- Lead 1 = positive
- AVF = positive
Ectopic Atrial Pacemaker
indicated by a QRS that is preceded by an abnormally oriented P wave
- II
- III
- aVF
leads that look at the inferior portion of the heart
- I
- aVL
- V5
- V6
leads that look at the lateral portion of the heart
- V3
- V4
leads that look at the anterior portion of the heart
- V1
- V2
leads that look at the septal portion of the heart
- AVR
- AVL
- AVF
unipolar limb leads
unipolar limb leads
- AVR
- AVL
- AVF
bipolar leads
- I
- II
- III
- I
- II
- III
bipolar limb leads
Lead I
measures for voltage between the left (positive) and right (negative) arm
- most useful for horizontal direction
Lead II
- right arm down to the left foot
- most valuable lead
Lead III
left arm to left foot
aVF
connect the two arms and compares it to the foot
aVL
compares the right arm, leg, and bisecting it by the leg
aVR
useless lead
V1
lead placed on 4th intercostal space on the right side of the sternum
V2
lead placed on the 4th intercostal space on the left peri-sternum
V3
lead put between 2 and 4 on the chest
V4
lead placed on the 5th intercostal space midclavicular line
V5
lead placed on the 5th intercostal space axillary line
V5
best lead to look for ischemia
V6
lead placed in the 5th intercostal space mid axillary line
Epinephrine, norepinephrine, atropine
- affect sympathetic activity of the heart
- speeds up the heart
- increase SA node pacing, increase conduction, increase force of contracility, increase everything
Acetylcholine, Vagus nerve
- affects parasympathetic activity of the heart
- slows heart down
slows down heart
stimulate vagus nerve
speeds heart up
cut/block vagus nerve
Atropine
drug that creates tachycardia
Adenosine
drops heart rate; give to people with tachycardia
Aminoderium
mellows out the heart
Class I agents
agents that interfere with the sodium channel
- i.e., Sodium Channel Blockers
Class I agents
Sodium Channel Blockers
Class II agents
anti-sympathetic nervous system agents
- i.e., Beta Blockers
Class II agents
Beta Blockers
Class III agents
agents that affect potassium efflux
- i.e., potassium channel blockers
Class III agents
potassium channel blockers
Class IV agents
agents that affect calcium channels and the AV node
- i.e., CCBs
Class IV agents
CCBs
Class V agents
agents that work by other/unknown mechanisms
- i.e., Digoxin
Class V agents
Digoxin
Digoxin
decreases conduction of electrical impulses through the AV node and increases vagal activity via its central action on the CNS
salvador dali sign / hockey stick sign
a unique downward curve of the ST segment
Supraventricular Tachycardia
- regular rhythm
- rate >140bpm
- narrow QRS
- cant tell if those are P waves
- adenosine
- valsalva
- carotid massage
Supraventricular Tachycardia Tratment
digoxin
A.Fib Treatment
Lown-Ganong Levine Syndrome and Wolf Parkinsons White Syndrome
- pre-excitation syndrome occurs when a band of conducting tissue bypasses the normal AV pathway
- QRS usually have an early upstroke of the R wave prior to a normal looking QRS
- Slurred QRS
Amiodarone or Lidocaine, procainamide and synchronized cardioversion electric shock
Ventricular Tachycardia Treatment
Polymorphic Ventricular Tachycardia (AKA Torsades)
- associated with hypokalemia and hypomagnesemia
- chaotic irregular electrical activity within ventricles with no visible QRS
Bundle Branch Blocks
- QRS is prolonged/wide
LBBB
QRS looks like a normal QRS but is wider and is NOTCHED (Soft M-shaped)
RBBB
QRS looks like cat ears (points)
Junctional Escape Beat/Accelerated Junctional DYsrhytmia
- absent P wave/hidden
- narrow QRS
Third Degree Heart Block
Paroxysmal AFIB
worst kind of AFIB
pause with visible P waves
what you will see in atrial escape beat
Transmural myocardial infarction
a myocardial infarction that involves the full thickness of the myocardium
Subendocardial myocardial infarction
a myocardial infarction that affects only the most sensitive inner part of the heart muscle
TSH to avoid thyroid storm
all patients with new onset AFIB should have what checked?
Junctional escape beat
pause but NO P wave however will see a narrow QRS
Ventricular escape beat
pause with NO P wave but a wide QRS
Causes of Ventricular Escape Beats/PVC
- low O2 status
- electrolyte imbalance
- exercise
- mitral valve prolapse
- A.Fib
- Multifocal Atrial Tachycardia
- Wandering Pacemaker
irregularly irregular rhythms
Irregularly Irregular Rhythms
- A.Fib
- Multifocal Atrial Tachycardia
- Wandering Pacemaker