Transcript EKG Interpretation - Fire Training Tracker

EKG Interpretation
Just the beginning
King County




Introduction
Cardiac monitoring has been routinely
used in the Fire Service for many years
Not without some liability
Intent of this course is to provide the
basics in cardiac rhythm interpretation
Introduction cont.




This course is not intended to teach
diagnosis of heart disease
Lead II is not sufficient for EKG
diagnosis
Recognition of the cardiac cycle will aid
in the understanding of EKG’s
In order to remain proficient it is
necessary to commit time to ongoing
training in EKG interpretation
Objectives




Understand basic cardiac terminology
Describe the anatomy of the heart
Identify the electrical conduction
system
Identify abnormal electrical cardiac
activity
Objectives


Identify common cardiac rhythms
Identify and effect appropriate therapy
for the patient on a monitor
Course Completion


Participants are expected to pass a
written exam and achieve a 70% score
Practical exam will include correct
interpretation of static rhythms, 70%
passing score
Primary Obligation




It cannot be overemphasized that the
primary obligation for non-cardiac
arrest patients is: ABC’s &
Attention to the patient’s symptoms
Vital Signs, physical exam
Any necessary treatment with
application of the monitor only when
basic life support has been completed
Anatomy & Physiology





Heart is a muscle
Divided into four chambers
Receives blood from the body via the
inferior and superior vena cavae
Chambers separated by valves
Coronary arteries supply blood to the
myocardium
Electrical Conduction System


Specialized system of interconnected
cells spread throughout the entire heart
Provides and conducts the signal to the
heart muscle to contract in a
coordinated fashion
Sinoatrial (SA) Node



Collection of electrical tissue that is the
normal point of origin of electrical
activity
Named because it is located in the sinus
part of the atria
Generates “P” waves
Atrioventricular (AV) Node



A way station that receives the impulses
from the atria
Named because it is located between
the atria and the ventricles
Actually used to slow impulses from the
atria to the ventricles
Bundle of His

Receives impulses from the AV node
and passes them through the left and
right bundle branches in the ventricular
septum
Purkinje Fibers



Last receiving point of the electrical
impulses
Fibers located in the ventricular
musculature
Rapidly conducts impulses causing
ventricular contraction
Automaticity


Any portion of the conduction system or
heart muscle may initiate an electrical
impulse
When the AV Node fails to generate an
impulse, another cell/area of the heart
will initiate electrical activity
Secondary Pacemakers


Any portion of the heart may initiate an
electrical impulse and becomes a
secondary pacemaker
Determining the location of a secondary
pacemaker will become clearer as we
proceed through this curriculum
Electrocardiographic paper
EKG paper





Grid of standard dimensions
Simply used as a measurement of time
Each small box represents 0.04 seconds
Larger bolded boxes are .20 seconds
Important to remember these values as
they aid in the identification of virtually
all EKG strips
The Cardiac Cycle



P wave- indicates atrial “depolarization”
PR interval- the interval from the
beginning of the P wave to the
beginning of the QRS complex
PR interval represents the time from
atrial depolarization to the beginning of
ventricular repolarization
Cardiac Cycle



Normal PR interval should not exceed
0.2 seconds or one large bolded square
on the EKG paper
QRS complex- represents electrical
depolarization of the ventricle
Normal duration of the QRS complex is
from 0.08-0.10 seconds (2 to 3 small
boxes on the EKG paper
Cardiac Cycle

T wave- represents repolarization of the
myocardium
Normal Sinus Rhythm






CharacteristicsP wave for each QRS
PR interval normal, <0.20 seconds
QRS complex is normal, <0.10 seconds
Uniform in shape
Rate is regular and is between 60-100
Normal Sinus Rhythm




Most common rhythm seen in acute MI
Does not indicate that the patient is
stable or that there is an absence of
heart disease
Indicates that the origin of the impulse
is from the SA Node
Indicates normal function of the
electrical system
Normal Sinus Rhythm
Normal Sinus Rhythm
Sinus Tachycardia






CharacteristicsP wave for each QRS
PR interval is normal, < 0.20 seconds
QRS complex is narrow, < 0.10 seconds
Uniform in shape
Rate is regular, > 100/minute
Sinus Tachycardia




Accelerated discharge of electrical
impulses from the sinus node
Treatment is “attention to symptoms”
Underlying cause is the concern
Causes include; shock, stimulants,
acute MI where decrease in cardiac
output causes heart rate increase
Sinus Tachycardia
Sinus Tachycardia
Supraventricular Tachycardia





P waves may not be seen due to
accelerated rate
QRS complex is narrow, < 0.10 seconds
Uniform in shape
Rate is regular, > 150/ minute
Patient’s heart rate is too fast
Supraventricular Tachycardia
Supraventricular Tachycardia
Sinus Bradycardia






CharacteristicsP wave for each QRS
PR interval is normal, < 0.20 seconds
QRS complex is normal, < 0.10 seconds
Uniform in shape
Rate is regular, < 60/ minute
Sinus Bradycardia




Transmission of impulses from the SA
node is slowed to < 60/ minute
Heart rates less than 50/ minute should
never be considered to be normal
Beta blockers, digoxin, hypoxia, being
athletic or with history of a slow heart
rate can be the cause
Patient’s heart rate is too slow
Sinus Bradycardia
Sinus Bradycardia
Premature Ventricular
Contractions




CharacteristicsEarly occurring beats that have a
characteristic “compensatory pause”
Premature QRS complex that is wide
and bizarre, conduction time > 0.10
seconds
Same shape except when from different
focus in the heart
Premature Ventricular
Contractions




Can occur in a healthy individual
Viewed with caution in the patient who
presents with cardiac symptoms
Significant if: occur in 2’s (couplets),
3’s (triplets),run of 4 is Ventricular
Tachycardia
Frequent occurring with syncope be
cautious
Premature Ventricular
Contractions
Ventricular Tachycardia





CharacteristicsP waves are usually present but are
obscured by wide, rapidly occurring
QRS complex
QRS complex is wide > 0.10 and bizarre
Uniform in shape typically
Rate is regular and > 150/ minute
Ventricular Tachycardia





Life threatening arrythmia
Rapid rate decreases cardiac output
Place patient supine, anticipating shock
Cause can be electrical and not always
acute MI
If patient unconscious and pulseless is a
a shockable rhythm
Ventricular Tachycardia
Ventricular Tachycardia
Idioventricular Rhythm





CharacteristicsP waves typically obscured or follow the
QRS complex
QRS complex is wide, > 0.10 seconds
Sometimes uniform in shape
Rate is irregular, most often seen with
rate < 40/minute
Idioventricular Rhythm





Observed after defibrillation & can be
endpoint in arrest resuscitation attempt
Conduction system above the ventricles
fails to generate an electricle impulse
Inherent rate of 30-40/minute
Will likely be in cardiac arrest
If unconscious and B/P <60, initiate
CPR
Idioventricular Rhythm
Ventricular Fibrillation






CharacteristicsP waves are absent
QRS complex absent
Baseline wavy, chaotic and inconsistent
Rhythm irregular
Rate is not countable
Ventricular Fibrillation



Sudden death & cardiac arrest
immediately follow the onset
Immediately defibrillate with 200 joules
and proceed with standing orders
Remember that we now do CPR for 2
minutes between shocks
Asystole





CharacteristicsP waves are not present
QRS complex is not present
Absence of any complexes indicate
complete cessation of electrical activity
The heart is motionless
Asystole
Pacemakers




CharacteristicsP waves sometimes are visible but are
not associated
QRS complex of times is wide, > 0.10
seconds
Preceded by a small spike with either a
negative or positive deflection
Pacemakers



Presence of a pacemaker indicates that
there is an underlying rhythm
disturbance, usually heart block
Technology makes it harder to see
when they are present
Failure can occur, look for pacer spikes
without complex initiated
Pacemakers


Look for the presence of Ventricular
Fibrillation in the patient who is in
cardiac arrest
Spikes will appear even in the presence
of fibrillatory waves
Paced Rhythm
Paced Rhythm (AV Sequential)
Atrial Pacemaker
Pacemaker Failure
Sinus Arrhythmia





CharacteristicsP waves for each QRS
PR interval is < 0.20 seconds
QRS complex is narrow, < 0.10 seconds
Rate varies, will speed up during
inhalation and slow down on expiration
Sinus Arrythmia


This rhythm is commonly found in
healthy children or athletic adults
Treat specific complaint or injury
Sinus Arrythmia
Atrial Flutter





CharacteristicsP waves are referred to as flutter waves
and are uniform in shape, resembling a
sawtooth pattern, mirror effect
QRS complex is narrow, < 0.10 seconds
Rate is both regular and irregular
Can be rapid, often seen at 150/minute
Atrial Flutter



This rhythm is rarely seen in patients
with healthy hearts
Can be seen in patients with heart
disease, acute MI, lung disease and
pulmonary embolism
Likes to go fast, needs ALS eval and is
never normal for patients
Atrial Flutter
Atrial Fibrillation




CharacteristicsP waves are not clearly visible or
uniform for each QRS complex
QRS complex is typically narrow, but
can be wide
Is irregular-irregular, depending on
ventricular response can be rapid
Atrial Fibrillation




Cells within the atria fire chaotically
Will be observed to have a rapid
ventricular response with new onset
Digoxin, beta blockers, calcium channel
blockers can be used to control rate
Also coumadin prescribed to reduce the
incidence of clots in the heart chambers
Atrial Fibrillation
Atrial Fibrillation
Atrial Fibrillation
Atrial Fibrillation
Nodal Rhythm





CharacteristicsP waves are absent
QRS complex is narrow, < 0.10 seconds
Uniform in shape
Rate is regular, typically > 40/minute
but may be in excess of 100/minute
Nodal Rhythm




Nodal rhythm occurs when the SA node
fails to function
Expect to see narrow QRS complex,
<0.10 seconds
Can be caused by Digitalis Toxicity,
acute MI, hypoxia, diseased sinus node
In some patients this may be their
normal rhythm
Nodal Rhythm
Nodal Rhythm
Accelerated Nodal Rhythm
First Degree Heart Block






CharacteristicsP wave for each QRS
PR interval is >0.20 seconds
Rate is regular
QRS complex is narrow, < 0.10 seconds
Uniform in shape
First Degree Heart Block



Occurs when there is delayed
conduction of an impulse through the
AV node
Patients presentation dictates need for
intervention
Some patients may have first degree
heart block as their primary rhythm
First Degree Block
First Degree Heart Block
First Degree Heart Block
First Degree Heart Block
Second Degree Heart Block
Wenckebach, Mobitz Type 1





CharacteristicsP waves are present
P wave occurs at a regular rate
QRS complex is uniform in shape and
narrow, <0.10 seconds
PR interval progressively lengthens until
QRS complex is dropped
Wenckebach, Mobitz Type 1



Sinus impulse is progressively delayed
through the AV node until no
conduction occurs
Causes include ischemic heart disease,
acute MI, digitalis toxicity
Patient’s presentation determines
intervention, if ventricular rate is slow
the patient may not have symptoms
Wenckebach, Mobitz Type 1
Wenckebach, Mobitz Type 1
Wenckbach, Mobitz Type 1
Second Degree Heart Block
Mobitz Type II





CharacteristicsP waves are present
P waves occur at a regular rate
PR interval is fixed , may be prolonged
On occasion there will be more than
one P wave for each QRS complex
Mobitz Type II



QRS complex may be narrow, < 0.10 or
may be wide, > 0.10
Series of non conducted P waves may
be seen (atrial depolarization only)
Ratio at which the QRS complex is
conducted varies and is noted as a
ratio, 2:1, 3:1, etc. (#P’s for each QRS
complex)
Mobitz Type II




Most often seen in the setting of acute
MI
Frequently have syncope associated
due to the slow rate
Commonly progresses to complete
heart block
ALS evaluation paramount, since patient
will often times be in shock
Mobitz Type II
Mobitz Type II
Mobitz Type II
Third or Complete Heart Block




CharacteristicsP waves occur at a regular interval,
typically at a rate of 60-100 beats/min.
P waves do not have a fixed, or
constant relationship to the QRS
complex
PR interval abnormally prolonged, >
0.20 and changing
Complete Heart Block



QRS complex may be narrow, < 0.10 or
wide, > 0.10 depending on where in
the heart the impulse originates
QRS rate is usually constant, typically
between 20-40 beats/min.
Indicates that there is no transmission
of impulses between the atria and the
ventricles
Complete Heart Block





Often occurs in the setting of acute MI
Can occur with Digitalis toxicity, elderly
with conduction system problems
May present with syncope
This type of heart block may be
transient
ALS evaluation paramount, since patient
will often times be in shock
Complete Heart Block
Complete Heart Block
Complete Heart Block
P.E.A.
Pulseless Electrical Activity






CharacteristicsP waves may be present
PR interval may be normal, < 0.20 sec.
QRS complex may be narrow, < 0.10 or
wide, > 0.10
Rate can be regular or irregular
Can be normal rhythm
P.E.A


Pulseless Electrical Activity is indicated
by the absence of a detectable pulse
and the presence of some type of
electrical activity
Seen during cardiac arrest secondary to
acute MI, pulmonary embolus, cardiac
tamponade, tension pneumothorax or a
hypovolemic state
P.E.A. (sinus tachycardia)
Treatment Protocols



Do not attempt to treat any patient
from what is seen on the monitor alone,
unless V. Tach with unconsciousness or
V. Fib.
Patient presentation will direct
intervention
Request ALS evaluation when possible
lethal arrythmias are identified
Ongoing Education



It is recommended that EMT’s receive
regular ongoing education to remain
proficient at EKG recognition
Quarterly review/refresher by a
paramedic or equivalent
Attach EKG strips to your MIRF forms
for department reviewer for feedback
and identification confirmation
EKG Interpretation


Questions?
The end or just
the beginning?