Care of the Patient with a Pacemaker

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Care of the Patient with a Pacemaker

• Becca Maddox
• NURS 2205
• Spring 2002

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Pacemakers

• Provides repetitive electrical stimuli to the
  heart muscle in order to control the heart rate
• Can be temporary or permanent
• Consist of a pulse generator and electrodes
  (leads)

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Temporary Pacemakers

• Types
• Transcutaneous external pacemaker
• Epicardial pacemaker
• Transthoracic thoracic pacemaker
• Transvenous endocardial pacemaker

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Temporary Pacemakers

• Indications
• Conduction disorders
• Rate disorders
• Prophylaxis

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Temporary Pacemakers

• Components
• Pulse generator
• Leads
• External
• Epicardial
• Transthoracic
• Transvenous

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Temporary Pacemakers

• Pacing systems
• Unipolar
• Bipolar
• Pacing cables
• Black Negative, pacing terminal
• Red Positive, ground terminal

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Temporary Pacemakers

• Insertion
• External - applied emergently at the bedside
• Epicardial - leads are placed by the cardiac
  surgeon in the operating room
• Transthoracic - Usually attempted emergently, as
  a last resort, after other temporary pacing
  methods have failed. Physician inserts a
  pericardial needle through the subxyphoid area of
  the thorax into the right ventricle and advances
  the lead wire through the needle in order to
  achieve contact with the endocardium
• Transvenous - May be inserted at the bedside,
  preferably under fluroscopy. Usually inserted
  into the subclavian or jugular vein, but can be
  inserted into the antecubital or femoral vein

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Temporary Pacemakers

• Settings
• Rate
• Fixed (Asynchronous)
• Stimulus is provided at a preset rate
• Rate is set greater than the patients inherent
  rate to avoid competition
• Demand (Synchronous)
• Stimulus is provided when the patients heart
  rate drops below at predetermined rate
• Must have adequate sensing

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Temporary Pacemakers

• Sensitivity Threshold
• Sensitivity
• Set in millivolts (mV)
• Allows pacemaker to detect the patients inherent
  R wave
• Sense Indicator
• Flashes when inherent R wave is detected
• Senses if pacing is in the demand mode
• Threshold
• The minimum R wave amplitude needed to be
  detected by the pulse generator
• Once the sensitivity threshold is determined, the
  sensitivity is set 2-3 times lower

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Temporary Pacemakers

• Stimulation Threshold
• Output/mA
• Stimulus current is measured in milliamperes (mA)
• Adjusted based on the amount of current needed to
  elicit myocardial depolarization and contraction
• variables - position of electrode contact with
  viable myocardial tissue level of energy
  delivered through wire presence of hypoxia,
  acidosis or electrolyte imbalances and other
  medications being used
• Pace indicator
• Flashes each time a pacing stimulus is generated
• Does not necessarily indicate that a cardiac
  contraction occurred
• Pacing Threshold
• The minimum amount of mAs needed to achieve 100
  capture
• The output is then doubled

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Temporary Pacemakers

• Pacing Modes
• Atrial asynchronous pacing - atrial fixed pacing
• Impulse initiated via the atria
• Pathway similar to normal conduction
• Can be initiated via epicardial atrial leads
• Can result in competition
• Used for asystole or symptomatic sinus
  bradycardia
• Contraindicated for atrial fibrillation or
  flutter and for person with conduction delays

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Temporary Pacemakers

• Ventricular synchronous pacing - ventricular
  demand pacing
• Impulse is sent to the ventricle when the
  patients inherent rate drops below the preset
  rate on the pulse generator
• No harmony between atria and the ventricle
• Used as a back up system for sinus bradycardia,
  heart blocks, atrial fibrillation/atrial flutter
  with SVR, junctional rhythm

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Temporary Pacemakers

• AV sequential asynchronous pacing - dual
  chambered fixed rate pacing
• Impulses sent to atria and ventricle at a
  predetermined rate and at a predetermined AV
  interval regardless of patients own rhythm
• Normal conduction through the heart
• Used for asystole, symptomatic sinus bradycardia,
  and for varying degrees of heart block to
  maintain AV conduction
• AV sequential synchronous pacing - dual chambered
  demand pacing
• Impulses sent to atria and ventricles when the
  patients rated drops below the preset rate on
  the pulse generator
• Normal conduction through the heart
• Used for asytole, symptomatic sinus bradycardia
  and heart block

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Temporary Pacemakers

• Special Considerations
• External Transcutaneous Pacing
• Cleanse skin with soap and water prior to
  applying patches
• Avoid using flammable skin preps such as alcohol
  or tincture of benzoin
• If hairy chest, clip hair instead of shave to
  avoid nicks
• Select a lead that maximized the R-wave amplitude
• Set pacemaker settings as prescribed or follow
  PP for the institution
• May need analgesics or sedatives to minimize pain

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Temporary Pacemakers

• Epicardial pacing
• Connect the negative pacing terminal to the
  epicardial lead electrode that is attached to the
  heart chamber to be paced
• Connect the positive ground terminal to another
  epicardial lead electrode, subcutaneous pacing
  wire, subcutaneous needle or skin patch electrode
• Determine sensitivity threshold and pacing
  threshold
• Set pacemaker settings
• Initiate pacing
• Be sure to follow hospital PP for initiating and
  adjusting pacemaker settings

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Temporary Pacemakers

• Transthoracic pacing - usually a last resort
• After emergency insertion is completed, assist
  with additional attempts to insert another type
  of temporary pacing or prepare family for
  insertion of a permanent pacemaker
• Transvenous pacing
• Obtaining pulmonary artery wedge pressures may be
  contraindicated if being paced via a pulmonary
  artery catheter
• If initiated through antecubital or femoral vein,
  limit mobility of the extremity
• Determine sensitivity and pacing thresholds
• Set pacemaker settings
• Initiate pacing
• Follow hospital PP for initiating and adjusting
  pacemaker settings

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Temporary Pacemakers

• Troubleshooting
• Failure to fire - cant see pacemaker spikes
  during periods of asystole or bradycardia
• Loose connections in the pacing system
• Failure of pacemaker battery or pulse generator
• Fracture of the pacing lead wire
• Lead wire dislodgement
• Failure to capture - pacemaker spike is not
  followed by a P wave or QRS as appropriate
• Loose connections in the pacing system
• Increased pacing threshold
• Fracture of the pacing lead wire
• Lead wire dislodgement
• Failure of pacemaker battery or pulse generator

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Temporary Pacemakers

• Undersensing - pacemaker fires with no regard to
  the patients own rhythm. Dangerous because it
  may lead to ventricular tachycardia and/or
  ventricular fibrillation
• Inadequate QRS signal
• Myocardial ischemia, fibrosis, electrolyte
  imbalances, bundle branch block, or a poorly
  positioned lead
• Oversensing - pacemaker thinks it detects a QRS
  complex, inhibits itself and doesnt fire
• Tall or peaked P waves or T waves
• Myopotentials (electrical signals produced by
  skeletal muscle contraction as with shivering or
  seizures)

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Temporary Pacemakers

• Patient Management
• ECG monitoring
• Hemodynamic monitoring
• Assess pacemaker function
• Electrical safety
• Reassess functioning after defibrillation
• Pacing insertion site care
• Assure pacemaker controls are protected from
  accidental adjustment
• Provide information regarding pacemaker therapy
  to the patient and family

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Permanent Pacemakers

• Lead Placement
• Epicardial
• Usually placed during heart surgery
• Leads placed in contact with epicardium
• Pulse generator in a subcutaneous pocket in
  abdomen
• Endocardial (Transvenous)
• Most common
• Pacing catheter inserted percutaneously via
  subclavian vein and advanced to the right atrium
  or apex of right ventricle
• Leads placed in contact with endocardium
• Pulse generator in subcutaneous pocket in the
  subclavian area

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Permanent Pacemakers

• Indications
• Symptomatic bradycardia
• Acquired atrioventricular block (including A-V
  block from an MI)
• Chronic bifasicular or trifasicular block
• Sinus node dysfunction, including sick sinus
  syndrome
• Hypersensitive carotid sinus disease
• Conduction system trauma (accident or cardiac
  surgery)
• Congenital anomalies
• Non reversible drug toxicities

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Permanent Pacemakers

• Components
• Pulse generator - consists of lithium batteries
  and electrical micro circuitry encased in
  titanium. Lithium batteries last about 5-10years,
  depending on how much the pacemaker is used
• Lead wire - a catheter with electrodes at the
  tip. Ventricular wires are easier to secure than
  atrial wires
• Electrode(s) - remember the negative electrode is
  the one that paces
• Unipolar electrode - negative electrode at the
  tip of the wire is in contact with the heart, the
  metal casing around the pulse generator acts as
  the positive pole, creates a large spike on ECG
  paper
• Bipolar electrode - negative electrode is at the
  tip and positive electrode is a few millimeters
  above it, creates a small spike on ECG paper

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Permanent Pacemakers

• Identification Code - 5 letters
• 1st - Chamber(s) paced
• 2nd - Chamber(s) sensed
• 3rd - Response to sensing
• 4th - Rate Modulation Programmability
• 5th - Antitachycardia Pacing Function

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Permanent Pacemakers

• Types
• Demand or synchronous - has a sensing circuit
  that monitors cardiac activity
• All permanent pacers with a lead wire in the
  ventricle are this type to avoid pacing during
  ventricular repolarization
• Fixed rate or asynchronous - does not have a
  sensing circuit

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Permanent Pacemakers

• Terminology
• Heart rate - often expressed in milliseconds (ms)
  rather than beats per minute
• Pacemaker timing
• Escape interval - interval from last intrinsic
  beat to next paced beat
• Pacing interval - interval from last paced beat
  to next paced beat
• AV interval - corresponds to PR interval,
  programmed in milliseconds, usually set within
  the normal PR interval range (125 ms, 150 ms, 175
  ms, or 200 ms)

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Permanent Pacemakers

• Examples
• Single Chamber VVI Pacemakers
• Advantages - simple one lead system where the
  lead wire is placed in the right ventricle
• Limitations - loss of AV synchrony, lack of rate
  variability
• usually placed in patients who have chronic
  atrial fibrillation with SVR
• VVIR pacers were developed to achieve rate
  variability - there is a sensor in the pulse
  generator that senses skeletal muscle activity

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Permanent Pacemakers

• Dual Chamber DDD Pacemakers
• Advantages - two lead system with one lead wire
  in the atrium and one lead in the ventricle,
  capable of pacing the atria and ventricles,
  preserves AV synchrony,
• Limitations -
• Patients with atrial fibrillation or atrial
  flutter - it cant capture the atrium. Pacer is
  confused by the atrial activity. This will not
  cause harm to the patient, but will deplete the
  batteries faster. Should be reprogrammed.
• Lack of rate variability - DDDR pacers were
  developed to achieve rate variability. As the
  sensor picks up skeletal muscle activity, the
  DDDR pacer will increase the atrial pacing rate.

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Permanent Pacemakers

• Programmable Features
• Lower rate limit (LRL) - Atrial pacing will only
  occur at the LRL. Ventricular pacing can occur
  anywhere between the lower rate limit and the
  upper rate limit
• AV interval
• Upper rate limit (UPR) - the fastest rate at
  which the ventricles can be paced in response to
  atrial activity
• VA interval - the length of time from an
  intrinsic or paced ventricular event to the next
  atrial event. This is not directly programmable
  but changes as other programmable parameters are
  changed. (LRL - AV interval)

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Permanent Pacemakers

• Modes of Operation
• Patient in sinus rhythm - atrial and ventricular
  pacers are inhibited
• Patient in atrial pacing only - atrial pacing
  occurs because patient cant initiate a sinus
  rate faster than the LRL of the pacer.
  Ventricular pacing is inhibited patient is able
  to conduct the impulse to the ventricles before
  the AV timer expires
• Patient in ventricular pacing only - atrial pacer
  is inhibited because of patients ability to
  initiate a sinus impulse faster than the LRL.
  Ventricular pacer is triggered because patient is
  not able to get the impulse to the ventricles
  before the AV timer expires
• Patient in AV pacing - atrial pacing occurs
  because of the patients inability to initiate a
  sinus impulse faster than the LRL and the
  ventricular pacer fires because the AV timer
  expires before impulse can travel to the
  ventricles

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Permanent Pacemakers

• Troubleshooting
• Failure to capture
• Reasons
• Lead dislodgement
• Lead fracture
• Loose connections between pulse generator and
  lead wire
• Fibrosis at the tip of the lead causing changes
  in the pacing threshold
• Treatment
• Obtain a chest x-ray to determine lead position
• Reposition or replace lead if dislodged or
  fractured
• Reprogram pacer if fibrosis is cause of failure
  to capture
• SQ pocket may need to be reopened to check
  connections
• Have atropine and external pacemaker at bedside
  in case patient develops a symptomatic bradycardia

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Permanent Pacemakers

• Failure to sense
• Reasons
• Electromagnetic interference
• Lead fracture
• Loose connections between the pulse generator and
  the lead wire
• Battery failure
• Treatment
• Move away from magnetic field
• Obtain a chest x-ray to determine lead position
• Reposition or replace lead if dislodged or
  fractured
• SQ pocket may need to be reopened to check
  connections
• Replace generator if needed
• If undersensing or oversensing and generator is
  programmable, need to reprogram

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Permanent Pacemakers

• Failure to fire
• Reasons
• Electromagnetic interference
• Lead fracture
• Loose connections between the pulse generator and
  the lead wire
• Circuitry or battery failure
• Treatment
• Move away from magnetic field
• Obtain a chest x-ray to determine lead position
• Reposition or replace lead if dislodged or
  fractured
• SQ pocket may need to be reopened to check
  connections
• Replace generator if needed
• Have atropine and external pacemaker at bedside
  in case patient develops a symptomatic
  bradycardia

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Permanent Pacemakers

• Patient Management
• Pre-op
• Avoid placing ECG monitoring electrodes over the
  right or left subclavian areas
• Patient and family teaching
• NPO after midnight
• Where procedure will be done and about how long
  it will take
• Pre-op medications - sedative and antibiotic
• Local anesthesia rather than general

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Permanent Pacemakers

• Immediate Post-op
• Patient and family teaching
• Frequent vital signs
• Bedrest up to 24 hours (depending on hospital)
• Limited range of motion in the affected arm
  Administration of antibiotics
• Pain at incision site
• Encourage coughing and deep breathing

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Permanent Pacemakers

• Post-op Nursing Management
• Document type of pacer and settings
• Run an initial strip and then one at least every
  4 hours - more often if pacing in noted on
  monitor
• Obtain a 12 lead ECG upon return
• Observe for appropriate pacemaker functioning
• Observe pressure dressing for signs of infection
• Administer antibiotics as prescribed
• Offer pain medicine at regular intervals

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Permanent Pacemakers

• Discharge Teaching
• Watch insertion site for signs of infection
• If sutures, they will be removed in one week. If
  steristrips, they will gradually fall off
• Return to activities gradually
• How to take a pulse
• Transtelephonic monitoring of pacemaker function
• Importance of follow-up visit
• Life of batteries
• New medications

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Permanent Pacemakers

• Pacemaker wallet identification card
• Medic alert bracelet application
• Avoid electromagnetic interference
• all household appliances, including microwave
  ovens, are OK to use
• avoid welding equipment power transmitters
  large generators radio, television, and radar
  towers - antennas at home are safe, but not CB
  and ham operator antennas
• avoid leaning directly over any running engines
  or motors - can create magnetic fields
• Bingo wands used in bingo halls and stereo
  speakers contain magnets. These devices should
  not come in contact with the pacemaker generator
  in the shoulder for any period or time

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Permanent Pacemakers

• avoid electrocautery and diathermy
• no MRI scan performed for other medical
  conditions
• inform other physician that they have a
  pacemaker, particularly dentists
• have wallet card available at airport metal
  detectors. Need to inform them to be careful of
  hand-held wands as they may have magnets in them
  and should therefore not be held over the
  pacemaker generator for a long period of time

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Permanent Pacemakers

• Rhythm Strip Interpretation
• If possible, find out what kind of pacemaker the
  patient has
• Look for presence of an underlying rhythm
• Look closely for the presence of a pacer spike
• Look for the presence of P waves (intrinsic or
  paced) and their rate and relationship to the QRS
  complexes
• Examine QRS complexes to determine if they are
  paced or intrinsic
• If ventricular pacing, note whether each beat is
  preceded by a P wave (paced or intrinsic) and
  whether the AV(PR) interval is constant before
  the ventricular paced beats
• Observe for fusion beats