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Chapter 37
Interventions for Clients with
Dysrhythmias
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Review of Cardiac Electrophysiology
• Automaticity
• Excitability
• Conductivity
• Contractility
• Action potential
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Cardiac Conduction System
• Sinoatrial node
– Electrical impulses at 60 to 100 beats/min
• Atrioventricular junctional area
• Bundle branch system
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Electrocardiography
• Electrocardiogram (ECG)
• Lead systems
• Limb leads
• Chest leads
• Continuous electrocardiographic monitoring
• Telemetry
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Electrocardiographic Complexes, Segments,
and Intervals
• P wave
• PR segment
• PR interval
• QRS complex
• QRS duration
• ST segment
• T wave
• U wave
• QT interval
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Electrocardiographic Rhythm Analysis
• Determine the heart rate.
• Determine the heart rhythm.
• Analyze the P waves.
• Measure the PR interval.
• Measure the QRS duration.
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Normal Rhythms
• Normal sinus rhythm
• Sinus arrhythmia
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Dysrhythmias
• Tachydysrhythmias
• Bradydysrhythmias
• Premature complexes
• Repetitive rhythms
• Escape complexes and rhythms
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Dysrhythmias
• Classification
• Sinus dysrhythmias
• Sinus tachycardia
• When the rate of SA node discharge exceeds
100 beats/min
• Clinical manifestations
• Interventions
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Sinus Bradycardia
• Rate of sinus node discharge < 60 beats/min
• Clinical manifestations
• Interventions
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Premature Atrial Complexes
• Ectopic focus of atrial tissue fires an impulse
before the next sinus impulse is due.
• Clinical manifestations
• Interventions
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Supraventricular Tachycardia
• Rapid stimulation of atrial tissue occurs at a rate
of 100 to 280 beat/min with a mean of 170
beats/min in adults.
• Paroxysmal supraventricular tachycardia rhythm
is intermittent and terminated suddenly with or
without intervention.
• Clinical manifestations
• Interventions
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Atrial Flutter
• Rapid atrial depolarization occurring at a rate of
250 to 350 times per minute
• Clinical manifestations
• Interventions
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Atrial Fibrillation
• Multiple, rapid impulses from many atrial foci at
a rate of 350 to 600 times per minute
• Clinical manifestations
• Interventions
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Premature Ventricular Complexes
• A result of increased irritability of ventricular
cells: early ventricular complexes followed by a
pause
• Clinical manifestations
• Interventions
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Ventricular Tachycardia
• Also called V tach: repetitive firing of an irritable
ventricular ectopic focus, usually at a rate of 140
to 180 beats/min
• Clinical manifestations
• Interventions
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Ventricular Fibrillation
• Also called V fib: a result of electrical chaos in
the ventricles
• Clinical manifestations
• Interventions
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Ventricular Asystole
• Also called ventricular standstill: complete
absence of any ventricular rhythm
• Clinical manifestations
• Interventions
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Decreased Cardiac Output and Ineffective
Tissue Perfusion
• Interventions include:
– Cardiac care
– Nonsurgical management
– Drug therapy
• Vaughn-Williams classification
• Other antidysrhythmic drugs
• Emergency cardiac drugs
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Nonsurgical Management
• Vagal maneuvers
• Carotid sinus massage
• Valsalva maneuvers
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Temporary Pacing
• Modes of pacing
– Synchronous pacing
– Asynchronous pacing
• Noninvasive temporary pacing
– Procedure
– Complications
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Invasive Temporary Pacing
• Procedure
• Complications
• Prevention of microshock
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Treatments
• Cardiopulmonary resuscitation
• Advanced cardiac life support
• Cardioversion: synchronized countershock that
may be used for emergent hemodynamically
unstable ventricular or supraventricular
tachydysrhythmias or electively for stable
tachydysrhythmias resistant to medical therapies
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Defibrillation
• Asynchronous countershock depolarizes a
critical mass of myocardium simultaneously to
stop the re-entry circuit and allow the sinus node
to regain control of the heart.
• Maintain a patent airway.
• Administer oxygen.
(Continued)
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Defibrillation (Continued)
• Assess vital signs and level of consciousness.
• Administer antidysrhythmic drugs.
• Monitor for dysrhythmias .
• Assess for burns, emotional support,
documentation.
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Other Therapies
• Automatic external defibrillation
• Radiofrequency catheter ablation
• Surgical procedures:
– Permanent pacemaker
– Coronary artery bypass grafting
– Aneurysmectomy
– Insertion of implantable
cardioverter/defribillator
– Open-chest cardiac massage
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