Transcript Cardiac Monitoring

Cardiac monitoring
Egan’s Ch. 17, CARC Ch. 11
Objectives (1 of 2)
1. To gain an understanding of basic
terminology and techniques of cardiac
monitoring.
2. To give you the knowledge and tools you
need to assist the advanced provider with the
use and implementation of an ECG.
3. To better understand the basic anatomy and
physiology of the heart.
Objectives (2 of 2)
4. Identify the components of basic cardiac
arrhythmias (because many times the RTs are
with the patient during the onset of the initial
event).
5. Evaluate the rate and rhythm of a patient’s
cardiovascular system, and become familiar
with the normal ECG.
6. Familiarize yourself with and apply 4-lead
electrodes and identify placements for the 12lead systems.
Cardiac Monitoring
• Use of 12-lead ECGs in the hospital is essential
for cardiac patients.
• Early identification of AMIs allows hospitals to
be prepared.
• The RT should know how to place electrodes
and leads.
Electrical Conduction System (1 of 2)
• A network of specialized cells in the heart
• Conducts electrical current throughout the
heart
• The flow of electrical current causes
contractions that produce pumping of blood.
VIDEO
The Process of
Electrical Conduction
• Electrical conduction occurs through a pathway of
special cells.
• Automaticity
– Ability of heart cells to generate a spontaneous
electrical impulse
• Sinoatrial (SA) node: the heart’s main pacemaker
– Paces at a ventricular rate of 60–100 beats/min
**Any beat that originates outside the SA node is called
“ectopic”**
The Process of
Electrical conduction
• Atrioventricular Junction- electrical bridge
between atria and ventricles, comprised of:
– (AV) node
– Bundle of His
• AV node
– Acts as secondary (backup) pacemaker
– Paces at a ventricular rate of 40-60 beats/min
– Impulse is temporarily delayed here to allow better
filling of the ventricles
– Protects ventricles from excessively fast rates
The Process of
Electrical conduction
• Bundle branches
• Purkinje fibers
– Fingerlike projections that pass electrical impulses
throughout myocardium to create a coordinated
contraction of the ventricles
Electrical Conduction System (2 of 2)
• VIDEO
Formation of the ECG (1 of 4)
Formation of the ECG (2 of 4)
Formation of the ECG (3 of 4)
Formation of the ECG (4 of 4)
Electrodes and Waves
Electrodes pick up electrical activity of the
heart.
The ECG Complex
One complex represents one beat in the
heart.
Complex consists of P, QRS, and T waves.
ECG Paper
Each small box on
the paper
represents 0.04
seconds.
Five small boxes in
larger box
represents 0.20
seconds.
Five large boxes
equal 1 second.
Normal Sinus Rhythm
Consistent P waves
Consistent P-R interval (0.12-0.20 seconds)
60–100 beats/min
QRS < 0.12 seconds
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Sinus Bradycardia
Consistent P waves
Consistent P-R interval
Less than 60 beats/min
Potential causes are: Hypoxia, hypothermia, heart
disease, electrolyte imbalances(hyperkalemia),
parasympathetic stimulation, hypothyroidism
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Sinus Tachycardia
Consistent P waves
Consistent P-R interval
100 – 160 beats/min
Potential causes are: Fever, pain, hyperthermia,
anxiety, medications, hypoxia, sympathetic
stimulation
First Degree Block
• Impulse delayed at AV node
• Prolonged PR interval
• There is always concern that the patient will
progress to the next worse rhythm
2nd Degree Type I (Wenckebach)
• PR progressively longer until a QRS is dropped.
2nd Degree Type II (Mobitz)
• Nonconducted P waves followed by conducted
P waves.
3rd Degree Heart Block
• Ventricles and atria beat independently of one
another.
• There is no relationship between the P waves
and QRS complexes
• The patient will need a pacemaker
– Usually a temporary pacer (TCP) until a permanent
one can be inserted
Atrial Flutter
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Rapidly firing ectopic site in atria
Characteristic “sawtooth” pattern
At risk for thrombi
Rate: 180-400 beats/min
May progress to atrial fibrillation
Atrial Fibrillation
• Multiple ectopic sites within atria
• Atrial rate > 350 beats/min
• Decrease in ventricular filling
PVC’s
• Wide and bizarre QRS complex is the most distinguishing
feature
• No P wave prior to PVC
• Bigeminyand trigeminy
• Unifocal and Multifocal
– Multifocal is more concerning because there are
multiple irritated areas in the ventricles
• Occasional PVC is ok but > 6/min is a sign of
irritability
• May progress to ventricular tachycardia
• Treatment
PVC’s
Supraventricular Tachycardia (SVT)
• Impulse moves from atria – ventricles – atria
(circular)
• Rate: 160-220 beats/min
• P waves may be unidentifiable, normal QRS
• Treatment
– If stable and narrow complex can try adenosine or
vagal maneuvers
– If unstable, then immediate cardioversion
Ventricular Tachycardia
Three or more PVC’s in a row
Rate: 100-250 beats/min
No distinguishable P waves
Precedes or follows V-fib
Treatment
If stable, treat with amiodarone
If unstable with a pulse, then cardioversion
Pulseless VT is treated with CPR and defibrillation just
like VF
Ventricular Fibrillation
 Rapid, completely disorganized rhythm
 Deadly arrhythmia that requires immediate
treatment
 A new onset is coarse and will progress to fine
VF which is harder to defibrillate
 Fine VF can be confused with asystole
 Treatment is CPR and immediate defibrillation
Pulseless Electrical Activity (PEA)
• Pattern does not generate a pulse.
• May show normal QRS complexes
• Can be any kind of a pattern from NSR to one
or two complexes
• Treatment is CPR and identify the cause (H’s
and T’s)
Asystole
• Complete absence of electrical cardiac
activity
• Patient is clinically dead.
• Decision to terminate resuscitation efforts
depends on local protocol.
Cardiac Monitors
• May be 3-, 4-, or 12-lead system
• Compact, light, portable
• Many monitors now combine functions
beyond ECG.
4-Lead Placement
Four leads are
called limb leads.
Leads must be
placed at least 10
cm from heart.
12-Lead ECG
• Used to identify possible myocardial ischemia
• Studies show 12-lead acquisition takes little
extra time.
• Early identification of acute ischemia and
accurate identification of arrhythmias
12-Lead Placement
Limbs leads placed
at least 10 cm from
heart.
Chest leads must be
placed exactly.
Lead Location
View
V1
4th intercostal space, right sternal border
Ventricular septum
V2
4th intercostal space, left sternal border
Ventricular septum
V3
Between V2 and V4
Anterior wall of left ventricle
V4
5th intercostal space, midclavicular line
Anterior wall of left ventricle
V5
Lateral to V4 at anterior axillary line
Lateral wall of left ventricle
V6
Lateral to V5 at midaxillary line
Lateral wall of left ventricle
Holter monitoring
• Portable, battery powered recording device
• Done over 24 hours
• Useful in patients experiencing irregular heart
beats on an inconsistent basis.
Troubleshooting
• Clean skin.
• Use benzoin.
• Shave hair.