Dual Chamber Temporary Pacing Operations

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Dual Chamber Temporary PacingOperations
Troubleshooting
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Indications for Dual Chamber Temporary Pacing

• Complete heart block
• Sinus bradycardia
• Bradycardia with congestive heart failure
• Atrial and/or ventricular ectopic arrhythmia
• Reentrant tachycardias
• During pulse generator replacement

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Indications for Dual Chamber Temporary Pacing

• Prior to the implant of a permanent pacemaker
• Temporary support of a patient after heart
  surgery
• Acute myocardial infarction complicated by heart
  block
• High rate burst stimuli for the treatment of
  some tachyarrhythmias

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The NASPE/BPEG Generic (NBG) Code
Position
I
II
III
IV
V
Category
Chamber(s)Paced
Chamber(s)Sensed
Response toSensing
ProgrammabilityRate Modulation
AntitachyarrhythmiaFunction(s)
O None A Atrium V Ventricle D Dual (AV)
O None A Atrium V Ventricle D Dual (AV)
O None T Triggered I Inhibited D Dual
(TI)
O None P Simple Programmable M
Multiprogrammable C Communicating R Rate
Modulation
O None P Pacing S Shock D Dual (PS)
ManufacturersDesignationOnly
S Single (A or V)
S Single (A or V)
Note Positions I through III are used
exclusively for antibradyarrhythmia function
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Asynchronous Modes
AOO
VOO
DOO
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DVI
1
2
3
4
5
6
AV interval (140 ms)
Lower rate 60 ppm V-A interval 860 ms
PVARP (250 ms)
indicates cycle restarted by sensed or paced
event
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DDD Pacing
Chamber Paced
Chamber Sensed
Action or Responseto a Sensed Event
D
D
D
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DDD Pacemaker

• Provides
• AV Synchrony
• Rate Variability
• Results in
• Changes in cardiac output
• Management of rhythm
• Improved quality of life

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Parameter Adjustments of theTemporary DDD
Pacemaker

• Lower Rate
• AV Interval
• Upper Rate
• Output
• Sensitivity
• Refractory Period(PVARP)

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ECG Function DDD Mode
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Timing Intervals in milliseconds (ms)
VA 750 ms
AV 250 ms
VV 1000 ms
DDD / 60 / 250 / 125 / 155
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Calculation of Atrial Escape Interval

• Atrial Escape Lower Rate AV
  Interval Interval
• VV AV VA (ms) (ms) (ms)
• (60 ppm) 1000 250 750
• (60 ppm) 1000 150 850
• (70 ppm) 850 200 650

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Proper Atrial Sensingis the Heart
ofPhysiologic Pacing
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A Pace / V Pace
AV Sequential Pacing
VA 750 ms
AV 250 ms
VV 1000 ms
DDD / 60 / 250 / 150
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A Pace / V Sense
Atrial Pacing with Normal AV Conduction
Programmed Lower Rate1000 msActual VV960 ms
DDD / 60 / 200 / 150
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A Sense / V Pace
Atrial Synchronous Pacing
Spontaneous Atrial Rate 55 ppm
Spontaneous Atrial Rate 110 ppm
DDD / 50 / 150 / 150
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A Sense / V Sense
Spontaneous P-Wave with Normal AV Conduction
Spontaneous Atrial Rate 65 ppm Spontaneous P-R
Interval 160 ms
DDD / 60 / 200 / 150
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Timing Operations of DDD Pacing
VentricularRate
UpperRate
AtrialTracking
LowerRate
Atrial Rate
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Definitions

• PVARP Post Ventricular Atrial Refractory Period
• Time after Vs or Vp when atrial rates are
  ignored
• AV Time from As or Ap to Vp in ms
• TARP Total Atrial Refractory Period in ms

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Refractory Period

• Increase to prevent
• T-wave sensing
• P-wave sensing
• Decrease to permit tachy pacing

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Wenckebach Operation
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Wenckebach Operation
AV
AV
W
AV
W
AV
W
AV
PVARP
PVARP
PVARP
PVARP
PVARP
Upper Rate
Upper Rate
Upper Rate
Upper Rate
Upper Rate
As
As
As
As
As
As
Vp
Vp
Vp
Vp
Vp
W Wenckebach Interval
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2 1 Block
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2 1 Block
AV
AV
AV
AV
PVARP
PVARP
PVARP
PVARP
Upper Rate
Upper Rate
Upper Rate
Upper Rate
As
As
As
As
As
As
As
As
Vp
Vp
Vp
Vp
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Physiology of Retrograde Conduction
1. Loss of A-V synchrony due to a PVC
2. Sensed retrograde activation
3. A-V interval initiated
PVC
4. Prolongation of A-V interval
5. Ventricular pacing synchrononized to
retrograde P-waves
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Pacemaker Mediated Tachycardia (PMT)

• Fast ventricular paced rhythm
• Synchronized to retrograde-conducted P-waves
• Not normal sinus tachycardia

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Thresholds
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Feature of the Temporary DDD Pacemaker

• Output Control

Atrial
Ventricular
Pulse Amplitude(ma)
Pulse Width(ms)
29
Feature of the Temporary DDD Pacemaker
Sensitivity
2.5
1.25
0.5
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Troubleshooting
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Undersensing

• Failure of the pacemaker to senseintrinsic
  R-waves or intrinsic P-waves

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Undersensing

• Battery depletion
• Decreased QRS voltage
• Fusion beat
• Dislodged/fractured lead
• Inappropriate sensitivity setting

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Oversensing

• Inhibition of the pacemaker by events the
  pacemaker should ignore, e.g. EMI, T-waves, and
  myopotential

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Oversensing

• Myopotential inhibition
• EMI
• T-waves outside of refractory period
• Dislodged/fractured lead
• Inappropriate sensitivity setting

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No Output

• Pacemaker fails to emit stimuliat the programmed
  intervals

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No Output
1
2
3
4
5
AP
AS
AP
AP
AP
VP
VP
VP
VP
VP
No atrial output (on ECG)

• Battery depletion/pacemaker off
• Oversensing

• Faulty cable connection
• Dislodged/fractured lead

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Loss of Capture

• Electrical stimuli delivered bythe pacemaker
  does not initiate depolarization of the atria or
  ventricle

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Loss of Capture
Atrial
Noncapture
Ventricular
Noncapture
Fusion

• Inappropriate output setting
• Increased resistance to conduction
• QRS complex not visible

• Dislodged/fractured lead
• Tissue is refractory
• Faulty cable connection

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Ventricular Safety Pacing
Ap
Vp
Ap Atrial Pace Vp Ventricular Pace
ProgrammedA-V Interval
Ventricular Blankingat Atrial Rate
12 ms
Ventricular SafetyPace Interval
110 ms
Programmed A-V Interval
Ventricular Sensing within this period triggers a
ventricular output at an A-V interval of 110 ms
instead of programmed A-V interval.
Ventricular Sensing during the remainder of the
programmed A-V interval inhibits the ventricular
output. If there is no sensed event, a
ventricular output occurs at the programmed A-V
interval.
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Ventricular Safety Pacing (VSP)
1
2
3
4
5
AV interval (160 ms)
Lower rate 54 ppm Upper rate 180 ppm V-A
interval 860 ms
PVARP (250 ms)
indicates cycle restarted by sensed or paced
event