Download DYSRHYTHMIAS

DYSRHYTHMIAS
NUR – 224
MS. GARDNER
DYSRHYTHMIAS
• Disorder of conduction of the electrical impulse
within the heart.
• Cause disturbances with heart rate/heart rhythm
or both.
• Diagnosed by analyzing the electrocardiographic
(ECG/EKG).
• Treatment based on frequency and severity of
symptoms
• Named according to the site of origin of the
impulse and the conduction involved.
Normal Electrical Conduction
• Electrical impulse stimulates and paces the cardiac
muscle and normally originates in the SA node.
• Rate 60-100 bpm
• All beats appear in a similar pattern, equally spaced, and
have three major units:
P wave, QRS complex, and T wave.
Heart/ECG
• Each wave represents transmission of an electrical
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impulse through the heart muscle (depolarization) 
causes the muscle to contract and eject blood.
P wave – reflects impulse going through the atria.
QRS complex - reflects impulse going through the
ventricles.
T wave - is produced by the electrical recovery
(repolarization) of the ventricle.
Depolarization – electrical stimulation/contraction
Repolarization – electrical relaxation
Normal Electric Pathway
• Electrical impulse originates in the sinoatrial (SA) node.
• The impulse spreads through the intra-atrial pathways to
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the atrio-ventricular(AV) node.
The structure of the AV node slows the electrical impulse
 giving the atria time to contract and fill ventricles with
blood. (atrial kick)
After a brief delay, the impulse continues through the
bundle of His, the R/L bundle branches, Purkinje fibers
located in the ventricular muscle.
This stimulation causes the ventricles to contract (systole)
The heart rate is influenced by the autonomic nervous
system  sympathetic/parasympathetic nerve fibers
Electrocardiogram
• Electrical impulse travels through the heart  the end
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product is an ECG.
ECG is obtained by placing electrodes on the body – on
the limbs and chest.
The electrodes create an imaginary line  lead.
Waveforms that appear on the paper/cardiac monitor
represent the electrical current in relation to the lead.
Electrodes are attached to a cable wire which may be
connected to ECG machine, cardiac monitor, telemetry
monitor, Holter monitoring.
12-lead ECG  10 electrodes, reflects the activity in the
left ventricle.
Interpretation
• ECG waveforms are printed on graph paper that is
divided by light and dark vertical and horizontal lines.
• ECG waveform moves to the top of the paper  positive
deflection
• ECG moves toward the bottom of the paper  negative
deflection
• Each waveform should be compared and examined with
others.
Interpretation
• ECG – composed of waveforms (P wave, QRS complex,
T wave)
P wave –
 first upward deflection represents atrial depolarization. usually
not more than 3 small blocks.
QRS complex –
 ventricular depolarization.
 consist of three deflections: Q wave, the first downward stroke,
R wave first upward stroke; S wave downward stroke following
the R wave.
 normal duration of the QRS complex is less than three small
blocks (0.12 seconds).
Interpretation
T wave
• represents ventricular repolarization/electrical recovery of the
ventricular contraction.
PR interval
• measures from the beginning of the P wave to the onset
of the Q wave.
• represents conduction of the impulse through the atria and into
the AV node.
ST segment
• begins at the end of the S wave and ends at the beginning of
the T wave.
U wave
Small upward deflection following the T wave. Seldom present.
Interpretation
PP interval
• measured from one P wave to the beginning to the next P
wave
• used to determine atrial rhythm and atrial rate
RR interval
• measured from one QRS complex to the next QRS
complex.
• RR interval used to determine ventricular rate and rhythm.
Analyzing the Rhythm Strip
• Count the number of complexes in a 6 –second strip and
multiply that number by 10. (useful for irregular rhythms)
Analyze in a systematic manner:
• Rhythm – regular
• Rate – 60-100 beats/minute
• P wave – present and upright /all shaped alike
• PR interval - P wave precedes QRS
duration (0.12 -0.20 sec.)
time interval same for all beats
• QRS interval – present /all shaped alike
duration not more than 3 small squares
(0.12 sec.)
Normal Sinus Rhythm
• Rhythm – regular
• Rate – 60-100 beats/minute
• P wave – present and upright /all shaped alike
• PR interval - P wave precedes QRS
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duration (0.12 -0.20 sec.)
time interval same for all beats
QRS interval – present /all shaped alike
duration not more than 3 small squares
(0.12 sec.)
Sinus Bradycardia
• Dysrhythmias heart rate below 60, complex remain
normal
• Causes: sleep, athletic training, hypothyroidism,
medications, myocardial infarction
• Atropine IV medication of choice for treatment
bradycardia
Sinus Tachycardia
• All complexes are normal. The heart rate is more than100.
• Causes:
Physiologic stress
Medication
• Treatment: usually secondary to factors outside the heart,
treatment is directed to treat the underlying cause
Sinus Arrhythmia
• All complexes are normal, but the heart rate is irregular.
• The rate increases with inspiration and decreases with
expiration
• Does not cause any significant hemodynamic effect and
usually is not treated
Atrial Dysrhythmias
• Portions of atrial tissue may become excitable
and initiate impulses.
• These impulses will control the heartbeat if they
occur at a rate faster than impulses from the SA
node.
• Premature atrial complex
• Atrial flutter
• Atrial fibrillation
Premature Atrial Complex
• A single complex beat that occurs when an electrical
impulse appears early in the cycle – before the next sinus
beat.
• Cause: caffeine, nicotine, anxiety, hypokalemia
• PACs are common normal heartbeats
• If infrequent - no treatment is necessary.
Atrial Flutter
• Is a rapid, regular fluttering of the atrium.
• The atrial rate is between 250/400 times/minute.
• P wave takes on a saw toothed appearance
• Cause: open heart surgery, valvular disease
• Treatment: Adenosine, vagal maneuvers, electrical
cardioversion, medications, catheter ablation
Atrial Fibrillation
• Uncoordinated atrial electrical activity that causes a rapid
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disorganization and uncoordinated twitching of the atria
P waves – (fibrillatory waves) assume different shapes
because they are coming from different foci in the atrium.
No PR interval can be determined
Cause: CAD, open heart surgery, obesity, diabetes
Treatment:
Ventricular Dysrhythmias
 Ventricular tissue becomes more excitable as a result of
ischemia, drug effect or electrolyte imbalance. These
dysrhythmias may diminish the ability of the heart to
function as a pump.
 Without adequate blood flow, all organs deteriorate.
 Premature ventricular complex
 Ventricular tachycardia
 Ventricular fibrillation
 Ventricular asystole
Premature Ventricular Complex
• Impulse that starts in the ventricles and is conducted
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throughout the ventricle before the next normal sinus
impulse.
Can occur in healthy people  coffee, smoking, alcohol.
PVCs are usually not serious
Treatment: correct the underlying cause, if PVCs are
frequent and consistent  amiodarone/lidocaine
Bigeminy, trigeminy, multifocal
Multifocal PVC - Quadrigeminy
Ventricular Tachycardia
• Three or more PVCs in a row, rate exceeds 100 bpm.
• Is an emergency the patient is usually unresponsive
and pulseless, leads to reduce cardiac output.
• Treatment: antiarrhythmic medication, pacing, or
cardioversion
• If patient is unconscious and without a pulse immediate
defibrillation
Ventricular Fibrillation
• Most common dysrhythmia in patients with cardiac arrest
• Rapid, disorganized ventricular rhythm that cause
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ineffective quivering of the ventricles
No atrial activity is seen on ECG
Characterized by: absence of an audible heartbeat, a
palpable pulse, and respirations
There is no coordinated cardiac activity  cardiac arrest
and death are imminent if the dysrhythmia is not corrected
Defibrillation/cardiopulmonary resuscitation (CPR)
Ventricular Asystole
Ventricular Asystole
• Flatline,
• No QRS complex
• P waves may be apparent for a short duration
• There is no heartbeat, no palpable pulse, and no
respiration
• Without immediately treatment – fatal
• Treatment – CPR, intubation, IV access
Assessment
• Cardiac dysrhythmias – either begin/critical
• Diagnostic Test
electrocardiogram
cardiac monitoring
electrophysiology
Nursing Interventions
• Monitoring/ECG monitoring
• Administration of medications/medication effects
• Adjunct therapy: cardioversion, defibrillation, pacemakers
• Other
Adjunctive Modalities
• Medications not working
• Common therapies:
elective cardioversion
defibrillation
implantable devices
internal cardio defibrillators
Pacemakers
 Is a pulse generator used to provide an electrical stimulus
to the heart when the heart fails to generate/conduct its
own rate that maintains cardiac output.
 Are programmed to stimulate the atria or the ventricles, or
both
 Pacing is detected on the ECG strip by the presence of
pacing artifact – a sharp spike is noted
• Power source may be internal/external
• Several different types:
Temporary
Permanent
Pacemaker
• Paces the heart when normal conduction
pathway is damaged.
• Basic unit – power source, one or more
conducting leads
• The electrical signal travels from the pacemaker,
through the leads, the walls of the myocardium.
• The myocardium is “captured” and stimulated to
contract
Pacemaker
• Permanent
• Implanted totally within the body
• The power source is placed subcutaneously,
usually over the pectoral muscle on the patient’s
nondominant side
• The pacing leads are leads are threaded
transvenously to right atrium and one/both
ventricles and attached to the power source.
Pacemakers
• Temporary
• Power source is outside the body
• Different types
Epicardial pacing
Transvenous pacing
Transcutaneous pacing
Epicardial pacing
Pacing on Demand
Pacemaker
Patient teaching
• Follow-up care
• Report s/s infection
• Keep incision dry
• Avoid lifting arm on pacemaker site
• Airport travel is not restricted
• Carry pacemaker information card
• Wear Medic-alert ID band
Cardioversion and Defibrillation
• Treat tachy dysrhythmias by delivering electrical
current that depolarizes myocardial cells
• When cells repolarize, sinus node usually able to
recapture role as heart pacemaker
• Cardioversion  current delivered is
synchronized with patient’s ECG
• Defibrillation  current delivered is
unsynchronized and immediate
Paddle placement
Cardioversion
• A synchronized circuit in the defibrillator delivers a direct
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electrical current synchronized with the patient’s heart
rhythm.
Countershock that is programmed to occur with the R
wave of the QRS complex.
Used for nonemergency basis –
Used to treat – atrial fibrillation, atrial flutter, stable
ventricular tachycardia
Patient is awake/hemodynamically stable
Sedation prior to the procedure
Patent airway
Initial energy less than what is needed for defibrillation –
50 – 100 joules
Defibrillation
• Choice of treatment of choice to terminate VF/pulseless
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VT.
Defibrillation is accomplished by delivering direct current
without regard to the cardiac cycle.
The output of the defibrillator is measured in joules/watts
– 200 -360 joules
If defibrillation is unsuccessful, CPR is immediately
initiated
Defibrillation, CPR, medication administration continues
until a stable rhythm resumes or until it is established that
the patient will not recover.
Safety Measures
• Assure good contact between skin, pads or paddles
• Use conductive medium, 20 to 25 pounds of pressure
• Place paddles so they do not touch bedding or clothing,
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are not near medication patches or oxygen flow
If cardioverting, turn synchronizer on
If defibrillating, turn synchronizer off
Do not charge device until ready to shock
Call “clear” three times; follow checks required for clear
Assure no one is in contact with patient, bed, or
equipment
Implantable Cardioverter Defibrillator
(ICD)
• Detect changes in cardiac rhythm and automatically
delivers an electric shock to convert the dysrhythmia back
into normal sinus rhythm.
• Used for sudden death survivors, recurrent ventricular
tachycardia
• Monitors the heart rate and rhythm and identifies VT.
Approximately 25 seconds after system detects a lethal
dysrhythmia, the mechanism delivers 25 joules or less of
shock to the patient’s heart.
• If the first shock is unsuccessful , the generator will
recycle itself and continue to deliver shock
ICD
Nursing Management
• Complications similar to those associated with pacemaker
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insertion
Avoid driving until instructed by HCP
No MRI
Air travel not restricted
If ICD fires – contact HCP immediately
If fires and client does not feel well – contact HCP
Medic-Alert ID
Caregivers should know CPR
Teaching – lifestyle changes, periodic device monitoring,
safety, surgical site care