Troubleshooting ICDs and Pacemakers

 
Legend:  † pacemaker,   ‡ ICD
     

Problem/Causes

Troubleshooting Tools

Programming Options

Oversensing

  • Concealed beats †
  • Electromagnetic interference (EMI)
  • Far-field sensing
  • Insulation break
  • Intermittent lead fracture
  • Loose setscrew
  • Myopotentials
  • T waves †
 
  • Chest x-ray
  • Deep breathing/Valsalva ‡
  • Counters/histograms †
  • EGMs/markers/intervals
  • Hysteresis on?
  • Impedance
  • Isometrics/arm movements
  • Patient history
  • Pocket manipulation
  • Programmable automatic gain control (AGC) ‡
  • Polarity †
  • Programmed parameters
  • Sensing threshold test †
  • Timing intervals
  • output in opposite chamber
  • refractory and/or blanking periods
  • sensitivity
 
     

Undersensing 

  • Dislodged lead
  • Inadequate cardiac signal
  • Insulation break
  • Lead fracture
  • Loose setscrew
  • Pseudofusion beats

 

  • Chest x-ray
  • Counters/histograms †
  • EGMs/markers/intervals
  • Impedance
  • Intrinsic amplitude test ‡
  • Pacing mode
  • Patient history
  • Polarity †
  • Programmed parameters
  • Refractory/blanking periods
  • Sensing threshold test †
  • or paced rate
  • refractory and/or blanking periods
  • sensitivity

 

     

Loss of Capture 

  • Battery depleted
  • Exit block
  • Insulation break
  • Lead dislodged
  • Lead fracture
  • Loose setscrew
  • Perforation
  • Twiddler’s syndrome

 

  • Battery voltage status
  • Chest x-ray
  • Counters/histograms †
  • EGMs/markers/intervals
  • Intrinsic amplitude test
  • Lead impedance
  • Magnet TMT †
  • Pace threshold test
  • Patient history
  • Pocket manipulation
  • Programmed parameters
  • output amplitude
  • pulse width

 

     

Loss of Output 

  • Battery depleted
  • Concealed stimuli on ECG
  • Insulation break
  • Lead fracture
  • Loose setscrew
  • Pacer inhibition
  • Polarity

 

  • Battery voltage status
  • Hysteresis on?
  • Pace (and shock ‡)  lead impedance
  • Magnet †
  • Programmed parameters
  • Pulse width
  • Shock energy level ‡
  • Voltage
  • output amplitude
  • pulse width
  • shock energy ‡
  • Verify polarity

 

Muscle Stimulation 

  • Current leakage – header
  • Insulation break
  • Lead dislodged
  • Unipolar pacing †
  • Chest x-ray
  • Direct observation
  • Output amplitude
  • Polarity †
  • Pulse width

 

  • Bipolar
  • output amplitude
  • pulse width

 

     

Failure to Convert Arrhyth.  ‡

  • Battery depleted                      
  • Exit block
  • Lead dislodged
  • Lead fracture
  • Leads reversed in header 
  • Loose setscrew 
  • Battery status
  • Shock energy level
  • Shock lead impedance

 

  • shock energy

 

     

High Lead Impedance ‡  

  • Lead fracture
  • Loose setscrew
  • Terminal lead pin not fully inserted in header
  • Bipolar/Unipolar readings
  • Daily measurements

 

  • Unipolar mode if appropriate
     

Low Lead Impedance ‡ 

  • Insulation break
  • Current leakage - header
  • Bipolar/Unipolar readings
  • Daily measurements

 

  • Unipolar mode if appropriate