Troubleshooting Part I

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TroubleshootingPart I
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Objectives

• Understand the four basic steps used to solve
  troubleshooting problems
• Identify ECG abnormalities that result from
  pacing system malfunction and pseudomalfunction
• Recognize data and resources available to aid in
  troubleshooting pacing system anomalies
• Discern pacemaker functions that can affect
  patient hemodynamics
• Describe the causes of pacemaker system anomalies
  and propose a potential solution

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The Steps Used in Troubleshooting Are Simple and
Remain the Same for Each Type of Problem

• Define the problem
• Identify the cause of the problem
• Correct the problem
• Verify the solution

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Defining the Problem and Identifying the Cause
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Potential Problems Identifiable on an ECG Can
Generally Be Assigned to Five Categories

• Undersensing
• Oversensing
• Noncapture
• No output
• Pseudomalfunction

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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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Undersensing May Be Caused By

• Inappropriately programmed sensitivity
• Lead dislodgment
• Lead failure
• Insulation break conductor fracture
• Lead maturation
• Change in the native signal

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Oversensing
...Though no activity is present
Marker channel shows intrinsic activity...
Ventricular Oversensing

• The sensing of an inappropriate signal
• Can be physiologic or nonphysiologic

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Oversensing May Be Caused By

• Lead failure
• Poor connection at connector block
• Exposure to interference

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Noncapture is Exhibited By

• No evidence of depolarization after pacing
  artifact

Loss of capture
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Noncapture May Be Caused By

• Lead dislodgment
• Low output
• Lead maturation
• Poor connection at connector block
• Lead failure

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Less Common Causes of Noncapture May Include

• Twiddlers syndrome
• Electrolyte abnormalities e.g., hyperkalemia
• Myocardial infarction
• Drug therapy
• Battery depletion
• Exit block

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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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No Output May Be Caused By

• Poor connection at connector block
• Lead failure
• Battery depletion
• Circuit failure

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Pseudomalfunctions

• Pseudomalfunctions are defined as
• Unusual
• Unexpected
• Eccentric
• ECG findings that appear to result from pacemaker
  malfunction but that represent normal pacemaker
  function

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Pseudomalfunctions May Be Classified Under the
Following Categories

• Rate
• AV interval/refractory periods
• Mode

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Rate Changes May Occur Due to Normal Device
Operation

• Magnet operation
• Timing variations
• A-A versus V-V timing
• Upper rate behavior
• Pseudo-Wenckebach 21 block
• Electrical reset
• Battery depletion
• PMT intervention
• Rate response

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Magnet Operation

• Magnet application causes asynchronous pacing at
  a designated magnet rate

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A to A vs. V to V Timing
A-A Timing
Atrial rate is held constant at 60 ppm
AV 200
AV 150
V-V Timing
V-A 800
V-A 800
Atrial rate varies with intrinsic ventricular
conduction
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Upper Rate Behavior

• Pseudo-Wenckebach operation will cause a
  fluctuation in rate

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Upper Rate Behavior

• 21 block operation will cause a drastic drop in
  rate

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Electrical Reset and Battery Depletion

• Reset may occur due to exposure to
  electromagnetic interference (EMI) e.g.,
  electrocautery, defibrillation, causing reversion
  to a back-up mode
• Rate and mode changes will occur
• Device can usually be reprogrammed to former
  parameters
• Elective replacement indicators (ERI) can
  resemble back-up mode
• Interrogating device will indicate ERI (Replace
  Pacer)

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PMT Intervention

• Designed to interrupt a Pacemaker-Mediated
  Tachycardia

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Rate Responsive Pacing

• An accelerating or decelerating rate may be
  perceived as anomalous pacemaker behavior

VVIR / 60 / 120
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Rate Changes May Occur Due to Therapy-Specific
Device Operation

• Hysteresis
• Rate drop response
• Mode switching
• Sleep function

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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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Rate Drop Response

• Delivers pacing at high rate when episodic drop
  in rate occurs
• Pacing therapy indicated for patients with
  neurocardiogenic syncope

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Mode Switching

• Device switches from tracking (DDDR) to
  nontracking (DDIR) mode

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Sleep Function
30 mins.
30 mins.
Wake Time
Bed Time
Time
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AV Intervals/Refractory Periods May Appear
Anomalous Due to

• Safety pacing
• Blanking
• Rate-adaptive AV delay
• Sensor-varied PVARP
• PVC response
• Noncompetitive atrial pace (NCAP)

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Safety Pacing

• Designed to prevent inhibition due to crosstalk
• Delivers a ventricular pace 110 ms after an
  atrial paced event

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Blanking
DDDR / 60 / 125 / 200 / 225
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Rate-Adaptive AV Delay

• AV interval shortens as rate increases

PAV delay with no activity 150 ms
PAV with activity 120 ms
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Sensor-Varied PVARP

• PVARP will shorten as rate increases

Long PVARP with little activity
Shorter PVARP with increased activity
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PVC Response

• PVARP will extend to 400 ms

DDD / 60 / 120 PVARP 310 ms
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Noncompetitive Atrial Pace (NCAP)

• Prevents atrial pacing from occurring too close
  to relative refractory period, which may trigger
  atrial arrhythmias

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A Change in Pacing Modes May Be Caused By

• Battery depletion indicators (ERI/EOL)
• Electrical reset
• Mode switching
• Noise reversion

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Noise Reversion

• Sensing occurring during atrial or ventricular
  refractory periods will restart the refractory
  period. Continuous refractory sensing is called
  noise reversion and will
• Cause pacing to occur at the sensor-indicated
  rate for rate-responsive modes
• Cause pacing to occur at the lower rate for non-
  rate-responsive modes

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Noise Reversion
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• Note Adverse patient symptoms may occur as a
  result of any of the previously mentioned pacing
  system malfunctions and some pseudomalfunctions.

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Management of Patient Symptoms May Be Necessary
as a Result of

• Muscle stimulation
• Palpitations
• Pacemaker syndrome
• Shortness of breath due to inappropriate rate
  response settings

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Muscle Stimulation May Be Caused By

• Inappropriate electrode placement near diaphragm
  or nerve plexus
• Break in lead insulation
• Unipolar pacing

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Palpitations May Manifest From

• Pacemaker syndrome
• Pacemaker-Mediated Tachycardia (PMT)

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Pacemaker Syndrome

• An assortment of symptoms related to the
  adverse hemodynamic impact from the loss of AV
  synchrony.

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Pacemaker Syndrome

• Symptoms include
• Dizziness
• Presyncope
• Chest tightness
• Shortness of breath
• Neck pulsations
• Apprehension/malaise
• Fatigue

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Pacemaker Syndrome May Be Caused By

• Loss of capture, sensing
• A-V intervals of long duration
• Onset of 21 block
• Single chamber system
• Absence of rate increase with exercise

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Pacemaker-Mediated Tachycardia (PMT)

• A rapid paced rhythm that can occur with atrial
  tracking pacemakers

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PMT is the Result of

• Retrograde conduction
• Tracking fast atrial rates (physiologic or
  non-physiologic)

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Retrograde Conduction
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Retrograde Conduction May Be Caused By

• Loss of A-V synchrony due to
• Loss of sensing/capture
• Myopotential sensing
• Premature ventricular contraction (PVC)
• Magnet application

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High Rate Atrial Tracking is Caused By

• Supra-ventricular tachyarrhythmias
• Atrial oversensing

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General Medtronic Pacemaker Disclaimer INDICATIONS
Medtronic pacemakers are indicated for rate
adaptive pacing in patients who may benefit from
increased pacing rates concurrent with increases
in activity (Thera, Thera-i, Prodigy, Preva and
Medtronic.Kappa 700 Series) or increases in
activity and/or minute ventilation
(Medtronic.Kappa 400 Series). Medtronic
pacemakers are also indicated for dual chamber
and atrial tracking modes in patients who may
benefit from maintenance of AV synchrony. Dual
chamber modes are specifically indicated for
treatment of conduction disorders that require
restoration of both rate and AV synchrony, which
include various degrees of AV block to maintain
the atrial contribution to cardiac output and VVI
intolerance (e.g., pacemaker syndrome) in the
presence of persistent sinus rhythm. 9790
Programmer The Medtronic 9790 Programmers are
portable, microprocessor based instruments used
to program Medtronic implantable
devices. 9462 The Model 9462 Remote Assistant is
intended for use in combination with a Medtronic
implantable pacemaker with Remote Assistant
diagnostic capabilities. CONTRAINDICATIONS Medtro
nic pacemakers are contraindicated for the
following applications        Dual chamber
atrial pacing in patients with chronic refractory
atrial tachyarrhythmias.        Asynchronous
pacing in the presence (or likelihood) of
competitive paced and intrinsic rhythms.       
Unipolar pacing for patients with an implanted
cardioverter-defibrillator because it may cause
unwanted delivery or inhibition of ICD
therapy.        Medtronic.Kappa 400 Series
pacemakers are contraindicated for use with
epicardial leads and with abdominal
implantation. WARNINGS/PRECAUTIONS Pacemaker
patients should avoid sources of magnetic
resonance imaging, diathermy, high sources of
radiation, electrosurgical cautery, external
defibrillation, lithotripsy, and radiofrequency
ablation to avoid electrical reset of the device,
inappropriate sensing and/or therapy. 9462 Operati
on of the Model 9462 Remote Assistant Cardiac
Monitor near sources of electromagnetic
interference, such as cellular phones, computer
monitors, etc. may adversely affect the
performance of this device. See the appropriate
technical manual for detailed information
regarding indications, contraindications,
warnings, and precautions.  Caution Federal law
(U.S.A.) restricts this device to sale by or on
the order of a physician.
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Medtronic Leads For Indications,
Contraindications, Warnings, and Precautions for
Medtronic Leads, please refer to the appropriate
Leads Technical Manual or call your local
Medtronic Representative.   Caution Federal law
restricts this device to sale by or on the order
of a Physician. Note This presentation is
provided for general educational purposes only
and should not be considered the exclusive source
for this type of information. At all times, it
is the professional responsibility of the
practitioner to exercise independent clinical
judgment in a particular situation.
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Continued inTroubleshootingPart II