Magnet Application

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Magnet Application
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Complications of Pacemaker Implantation
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Complications of Pacemaker Implantation

• Venous access
• Infection
• Thrombophelbitis
• Pacemaker Syndrome

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Venous Access

• Bleeding
• Pneumo / hemothorax
• Air embolism

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Infection

• 2 for wound and pocket infection
• 1 for bacteremia with sepsis
• S. aureus and S. epidermidis
• If bacteremic start Vancomycin, remove system,
  TV pacemaker and IV abx for 4-6 weeks, new system

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Thrombophlebitis

• Incidence 30-50
• 1/3 have complete venous obstruction
• b/c of collateralization only 0.5-3.5 devp
  symptoms
• Swelling, pain, venous engorgement
• Heparin, lifetime warfarin

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Pacemaker Syndrome

• Presents w/ worsening of original Sx post-implant
  of single chamber pacer
• AV asynchrony? retrograde VA conduction ? atrial
  contraction against closed MV TV ? jugular
  venous distention atrial dilation ? sx of CHF
  and reflex vasodepressor effects
• Dx of exclusion
• Tx w/ dual chamber pacer

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Pacemaker syndrome
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Pacemaker Malfunction
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4 broad categories

1. Failure to Output
2. Failure to Capture
3. Inappropriate sensing under or over
4. Inappropriate pacemaker rate

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Failure to Output

• absence of pacemaker spikes despite indication to
  pace
• dead battery
• fracture of pacemaker lead
• disconnection of lead from pulse generator unit
• Oversensing
• Cross-talk atrial output sensed by vent lead

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No Output

• Pacemaker artifacts do not appear on the ECG
  rate is less than the lower rate

Pacing output delivered no evidence of pacing
spike is seen
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Failure to capture

• spikes not followed by a stimulus-induced complex
• change in endocardium ischemia, infarction,
  hyperkalemia, class III antiarrhythmics
  (amiodarone, bertylium)

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Failure to sense or capture in VVI
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A failure to capture atria in DDD
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Inappropriate sensing Undersensing

• Pacemaker incorrectly misses an intrinsic
  deoplarization ? paces despite intrinsic activity
• Appearance of pacemaker spikes occurring earlier
  than the programmed rate overpacing
• may or may not be followed by paced complex
  depends on timing with respect to refractory
  period
• AMI, progressive fibrosis, lead displacement,
  fracture, poor contact with endocardium

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Undersensing

• Pacemaker does not see the intrinsic beat, and
  therefore does not respond appropriately

Scheduled pace delivered
Intrinsic beat not sensed
VVI / 60
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Undersensing

• An intrinsic depolarization that is present, yet
  not seen or sensed by the pacemaker

P-wavenot sensed
Atrial Undersensing
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Inappropriate sensing Oversensing

• Detection of electrical activity not of cardiac
  origin ? inhibition of pacing activity
• underpacing
• pectoralis major myopotentials oversensed
• Electrocautery
• MRI alters pacemaker circuitry and results in
  fixed-rate or asynchronous pacing
• Cellular phone pacemaker inhibition,
  asynchronous pacing

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Oversensing
...though no activity is present
Marker channel shows intrinsic activity...

• An electrical signal other than the intended P or
  R wave is detected

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Inappropriate Pacemaker Rate

• Rare reentrant tachycardia seen w/ dual chamber
  pacers
• Premature atrial or vent contraction ? sensed by
  atrial lead ? triggers vent contraction ?
  retrograde VA conduction ? sensed by atrial lead
  ? triggers vent contraction ? etc etc etc
• Tx Magnet application fixed rate, terminates
  tachyarrthymia,
• reprogram to decrease atrial sensing

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Causes of Pacemaker Malfunction

• Circuitry or power source of pulse generator
• Pacemaker leads
• Interface between pacing electrode and myocardium
• Environmental factors interfering with normal
  function

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Pulse Generator

• Loose connections
• Similar to lead fracture
• Intermittent failure to sense or pace
• Migration
• Dissects along pectoral fascial plane
• Failure to pace
• Twiddlers syndrome
• Manipulation ? lead dislodgement

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Twiddlers Syndrome
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Twiddlers Syndrome
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Leads

• Dislodgement or fracture (anytime)
• Incidence 2-3
• Failure to sense or pace
• Dx w/ CXR, lead impedance
• Insulation breaks
• Current leaks ? failure to capture
• Dx w/ measuring lead impedance (low)

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Cardiac Perforation

• Early or late
• Usually well tolerated
• Asymptomatic ? incd pacing threshold, hiccups
• Dx P/E (hiccups, pericardial friction rub), CXR,
  Echo

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Environmental Factors Interfering with Sensing

• MRI
• Electrocautery
• Arc welding
• Lithotripsy
• Cell phones
• Microwaves
• Mypotentials from muscle

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Management
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Management History

• Most complications and malfunctions occur within
  first few weeks or months
• pacemaker identification card
• Syncope, near syncope, orthostatic dizziness,
  lightheaded, dyspnea, palpitations
• Pacemaker syndrome diagnosis of exclusion

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Management Physical Exam

• Fever think pacemaker infection
• Cannon a waves AV asynchrony
• Bibasilar crackles if CHF
• Pericardial friction rub if perforation of RV

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Management adjuncts

• CXR determine tip position
• ECG

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Potential Problems Identifiable on an ECG Can
Generally Be Assigned to Five Categories

• Failure to output
• Failure to capture
• Undersensing
• Oversensing
• Pseudomalfunction

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Pseudomalfunction Hysteresis

• Allows a lower rate between sensed events to
  occur paced rate is higher

Hysteresis Rate 50 ppm
Lower Rate 70 ppm
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Management ACLS

• Drug and Defibrillate as per ACLS guidelines
• However keep paddles gt10cm from pulse generator
• May transcutaneously pace
• Transvenous pacing may be inhibited by venous
  thrombosis may need flouroscopic guidance

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AMI Pacers

• Difficult Dx most sensitive indicator is ST-T
  wave changes on serial ECG
• If clinical presentation strongly suggestive then
  should treat as AMI
• Coarse VF may inhibit pacer (oversensing)
• Successful resuscitation may lead to failure to
  capture (catecholamines, ischemia)

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Disposition
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Disposition

• Admit
• Pacemaker infections /unexplained fever or WBC
• Myocardial perforation
• Lead or dislodgement
• Wound dehiscence / extrusion or erosion
• Failure to pace, sense, or capture
• Ipsilateral venous thrombosis
• Unexplained syncope
• Twiddlers syndrome

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Disposition

• Potentially fixable in ED w/ help
• Pacemaker syndrome
• Pacemaker-mediated tachycardia
• Cross-talk
• Oversensing
• Diaphragmatic pacing
• Myopotential inhibitors

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Internal Cardiac Defibrillators
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Internal Cardiac Defibrillators

• Device to treat tachydysrhythmias
• If ICD senses a vent rate gt programmed cut-off
  rate of the ICD ? device performs
  cardioversion/defibrillation
• All ICDs are also vent pacemakers
• Required shock is approximately lt15 Joules
• Similar problems with implantation as pacemakers

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Indications for ICD

• Cardiac arrest from VF or VT not due to
  reversible etiology
• Spontaneous sustained VT
• Syncope NYD inducible symptomatic VF or VT in
  setting of poor drug tolerance or efficacy
• Non-sustained VF or VT CAD, prior MI, LV
  dysfunction and inducible VF or VT not responding
  to Class I antiarrhythmic Tx

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ICD Malfunction

• Inappropriate Cardioversion
• Ineffective Cardioversion
• Failure to Deliver Cardioversion

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Inappropriate Cardioversion

• Most frequently associated problem
• Sensing malfunction SVT sensed as VT
• Shocks for nonsustained VT
• T waves detected as QRS complex and interpreted
  as ? HR
• h/r Could be ? incidence of VT, VF (hypoK,
  hypoMg, ischemia /- infarction)

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Ineffective Cardioversion

• Inadequate energy output
• Rise in defibrillation threshold ?
  antiarrhythmics
• MI at lead site
• Lead fracture
• Dislodgement of leads

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Failure to Deliver Cardioversion

• Failure to sense
• Lead fracture
• Electromagnetic interference
• Inadvertent deactivation

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ACLS Interventions

• ICD may not prevent sudden cardiac death
• Same approach as with pacemakers
• Person performing CPR may feel a mild shock if
  ICD discharges during compressions
• Can deactivate device with magnet during
  resuscitation efforts

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Disposition

• in almost all instances, admission to a
  monitored setting with extended telemetric
  observation will be necessary
• Rosens

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Thanks to

• Calgary Health Region Pacemaker nurses
• Karen and Sandra

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References

• Brady et al. 1998. EM Clinics NA. 16(2) 361-388
• Xie et al. 1998. Em Clinics NA. 16(2) 419-462
• Shah et al. 1998 EM Clinics NA. 16(2) 463-487
• Harrigan and Brady. 2000. EMR 21(19) 205-216
• Rosen
• American College of Cardiology ECG of the Month
  Feb 2001 http//www.acc.org/education/online/ecg
  _month/0201/Feb01_02.htm
• Pacemaker and Automatic Internal Cardiac
  Defibrillator, Weinberger et. al
  http//www.emedicine.com/emerg/topic805.htm
• CorePace presentation 99912 by Medtronic Inc.
  2000 available from Pacmaker Nurses at Foothills
  Hospital, www.medtronic.com