1. Dual Chamber Temporary Pacing Operations & Troubleshooting

2. 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

3. 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

4. The NASPE/BPEG Generic (NBG) Code
Position I II
III IV V
Category
Chamber(s) Paced
Chamber(s) Sensed
Response to Sensing
Programmability Rate Modulation
Antitachyarrhythmia Function(s)
O = None
A = Atrium
V = Ventricle
D = Dual (A+V)
O = None
A = Atrium
V = Ventricle
D = Dual (A+V)
O = None
T = Triggered
I = Inhibited
D = Dual (T+I)
O = None
P = Simple Programmable
M = Multiprogrammable
C = Communicating
R = Rate Modulation
O = None
P = Pacing
S = Shock
D = Dual (P+S)
Manufacturer’s Designation Only
S = Single (A or V)
S = Single (A or V)
Note: Positions I through III are used exclusively for antibradyarrhythmia function

5. Asynchronous Modes
AOO
VOO
DOO

6. DVI 1 2 3 4 5 6 Vs ° Vp * Ap = AV interval (140 ms)
Lower rate = 60 ppm
V-A interval = 860 ms
= PVARP (250 ms)
= indicates cycle restarted by sensed or paced event

7. Action or Response to a Sensed Event
DDD Pacing
Chamber Paced
Chamber Sensed
Action or Response to a Sensed Event D D D

8. DDD Pacemaker Provides: Results in: AV Synchrony Rate Variability
Changes in cardiac output
Management of rhythm
Improved quality of life

9. Parameter Adjustments of the Temporary DDD Pacemaker
Lower Rate
A–V Interval
Upper Rate
Output
Sensitivity
Refractory Period (PVARP)

10. ECG Function DDD Mode

11. Timing Intervals in milliseconds (ms)
A–V
250 ms
V–V
1000 ms
DDD / 60 / 250 / 125 / 155

12. Calculation of Atrial Escape Interval
Atrial Escape Lower Rate – A–V Interval = Interval
V–V – A–V = V–A (ms) (ms) (ms)
(60 ppm) 1000 – 250 = 750
(60 ppm) 1000 – 150 = 850
(70 ppm) 850 – 200 = 650

13. Proper Atrial Sensing is the “Heart” of Physiologic Pacing

14. A Pace / V Pace A–V Sequential Pacing V–A 750 ms A–V 250 ms V–V
DDD / 60 / 250 / 150

15. Programmed Lower Rate 1000 ms Actual V–V 960 ms
A Pace / V Sense
Atrial Pacing with Normal A–V Conduction
Programmed Lower Rate 1000 ms Actual V–V 960 ms
DDD / 60 / 200 / 150

16. A Sense / V Pace Atrial Synchronous Pacing
Spontaneous Atrial Rate = 55 ppm
Spontaneous Atrial Rate = 110 ppm
DDD / 50 / 150 / 150

17. A Sense / V Sense Spontaneous P-Wave with Normal A–V Conduction
Spontaneous Atrial Rate = 65 ppm
Spontaneous P-R Interval = 160 ms
DDD / 60 / 200 / 150

18. Timing Operations of DDD Pacing
Ventricular Rate
Upper Rate
Atrial Tracking
Lower Rate
Atrial Rate

19. Definitions PVARP – Post Ventricular Atrial Refractory Period
Time after Vs or Vp when atrial rates are ignored
A–V – Time from As or Ap to Vp in ms
TARP – Total Atrial Refractory Period in ms

20. Refractory Period T-wave sensing P-wave sensing Increase to prevent:
Decrease to permit tachy pacing

21. Wenckebach Operation

22. Wenckebach Operation W = Wenckebach Interval 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

23. 2 : 1 Block

24. 2 : 1 Block As As As As As As As As Vp Vp Vp Vp AV AV AV AV PVARP
Upper Rate
Upper Rate
Upper Rate
Upper Rate As As As As As As As As Vp Vp Vp Vp

25. 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

26. Pacemaker Mediated Tachycardia (PMT)
Fast ventricular paced rhythm
Synchronized to retrograde- conducted P-waves
Not normal sinus tachycardia

27. Thresholds

28. 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

30. Troubleshooting

31. Undersensing
Failure of the pacemaker to sense intrinsic R-waves or intrinsic P-waves

32. Undersensing Battery depletion Decreased QRS voltage Fusion beat
Dislodged/fractured lead
Inappropriate sensitivity setting

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

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

35. No Output
Pacemaker fails to emit stimuli at the programmed intervals

36. No Output Faulty cable connection Dislodged/fractured lead1 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

37. Loss of Capture
Electrical stimuli delivered by the pacemaker does not initiate depolarization of the atria or ventricle

38. Loss of Capture Inappropriate output setting Dislodged/fractured lead
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

39. Ventricular Safety Pacing
Ap = Atrial Pace
Vp = Ventricular Pace Ap Vp
Programmed A-V Interval
Ventricular Blanking at Atrial Rate
12 ms
Ventricular Safety Pace 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.

40. Ventricular Safety Pacing (VSP)1 2 3 4 5 Vs Vp * Ap
= 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