1. Upper Rate Behavior

2. Why do we have Upper Rate Responses?
Reduce incidence of tracking inappropriate rhythm and/or rate

3. Upper Rate Response Initiating Factors
Exercise
Sinus Tachycardia
Atrial Arrhythmia
Sensing of Myopotentials
VA conduction exceeding PVARP

4. Upper Rate Response Limit
Fastest Atrial rate at which consecutively paced ventricular complexes maintain 1:1 synchrony
Also known as:
Ventricular Maximum Rate (VMR)
Maximum Tracking Rate (MTR)

5. Max Track Rate / Max Sensor Rate
Definitions
The Max Track Rate, or Maximum Tracking Rate, is the fastest rate that intrinsic P-waves can be tracked, or followed by paced Ventricular events with a 1:1 ratio.
The Max Sensor Rate, is the fastest rate the atria and the Ventricles can be paced, based upon sensor input.

6. DDD Timing A A VI VI PV PVARP Atrial Channel PVAB BL VRP
Ventricular Channel
URI

7. Max Track Rate
The fastest rate the Ventricular channel can pace when tracking intrinsic P-waves.

8. Max Track Rate
Programmed settings should be based on
Patient activity levels
Age (220 – age)
LV function
Chest pain
Tolerance by the Patient if a PMT occurs

9. Max Track Rate
Questions to consider
Can the programmed Max Track Rate be tolerated by the patient for prolonged periods?
During sinus tachycardia, can a sudden drop in the pacing rate be tolerated?

10. Upper Rate Behaviors
Fixed-Ratio block/Multiblock (2:1, 3:1, etc)
Wenckebach behavior (Pseudo, Electronic)
Auto Mode Switch (not in this presentation)

11. Upper Rate Behaviors
Depends on programmed values:
Max Tracking Rate
Sensed AV Delay
PVARP

12. Upper Rate Behavior
Fixed Ratio Block

13. Fixed-Ratio Block (Multiblock)
Fast Upper Rate Response
Simplest way to control upper rate
TARP = MTR AV
PVARP
TARP (Total Atrial Refractory Period)

14. 2:1 Block (one v-paced event per two p-waves)
Fixed-Ratio Block
2:1 Block (one v-paced event per two p-waves)
MTR = 115bpm AVD = 160ms PVARP = 360 ms

15. Fixed-Ratio Block Calculation
60,000 / TARP: e.g. 60,000 / 440 ms = 136 BPM
(2:1 block point) PV
PVARP
160 ms ms
TARP = 440 ms

16. Fixed-Ratio Block
PV interval always remains constant
May be inappropriate in young or physically active patients due to sudden rate drops
Patient tracks P-waves until the atrial rate gets to the 2:1 block
The Ventricular rate will suddenly go to half the Atrial rate

17. Fixed-Ratio Block
Fall Down Rate

18. 2:1 blocking Ex.: Shipped Settings PV Delay 150 ms PVARP 275 ms
Atrial rate
Stimulated ventricular rate
Ex.: Shipped Settings
PV Delay 150 ms
PVARP 275 ms
2:1-blockpoint 142 min-1
160
140
120
100
In shipped settings, the 2:1 block rate is quite low! This would affect pacing in normal, physiologic rate range of many patients and has to be dealt with. 80 60
Sensed Atrial Rate 80
100
120
140
160

19. Upper Rate Responses
Wenckebach

20. Upper Rate Behavior
Wenckebach block

21. Do you remember?
AV Block 2nd degree Mobitz I

22. Wenckebach
Max Track (MTR) must be programmed slower than the TARP interval
2:1 fixed-ratio block will occur when the P-P intervals become faster than TARP

23. Wenckebach Base Rate Interval AV AV PV V-A Interval PVARP MTR TARPAp Vp P P P
Base Rate Interval AV AV PV
V-A Interval
PVARP
MTR
TARP
W-Period

24. Wenckebach behaviour
Look at the VV and AV intervals

25. Wenckebach
Provides a smoother transition from 1:1 to 2:1 block
Avoids a sudden reduction of the ventricular pacing rate and maintains some degree of AV synchrony

26. Wenckebach response to increasing Atrial rates
Plateau
3:1
Ventricular
Rate
(paced)
1:1
2:1 . . . . . . .
Lower
Rate
MTR
TARP
ARRP
Atrial Rate (sensed)

27. Wenckebach
Example
DDD
MTR 100 bpm (600 ms)
AV delay 150 ms
PVARP 250 ms
TARP = 400 ms \150ppm
Therefore, atrial rates >100 bpm (600 ms) but < 150 bpm will result in Wenckebach behavior
Max PV delay prolongation is 200 ms ( )
PV intervals will vary from ms

28. Wenckebach
Calculation to determine if a Wenckebach is present:
Programmed MTR minus TARP
In our example: 600 ms ms = 200 ms
We have a 200 ms Wenckebach window

29. Atrial Rate Continuum Base Rate 60 PPM MTR 130 PPM AV delay 170 MS
PVARP 250 MS
60 PPM
130 PPM
143 PPM
Base Rate
(MTR)
TARP
Device
Response
1:1 Tracking
Wenckebach
2:1 Block
TARP = PV Delay + PVARP =
= 420 ms 143 PPM (2:1 Block Point)

30. Wenckebach 150 ms 600 ms 200 ms Base Rate Interval AV AV PVAp Vp P P P
Base Rate Interval AV AV PV
150 ms
V-A Interval
PVARP
600 ms
MTR
TARP
200 ms
W-Period

31. Pseudo Wenckebach - Upper Rate Behaviour
A-A
AV Delay
PVARP
VRP
MTRI
Maximum Tracking Rate Interval

32. Wenckebach Base Rate 60 ppm MTR 120 ppm AV 200 ms PV 150 ms
Min. PV ms
PVARP 250 ms

33. Wenckebach P-wave in alert and sensed
PVARP
MTR
Ventricular pacing at Max Tracking Rate
Base Rate 60 ppm
MTR 120 ppm
AV 200 ms
PV 150 ms
Min. PV ms
PVARP 250 ms

34. Wenckebach
Identification
Variable PV delays
Sustained high rate pacing
Occasional change in the beat to beat ventricular rate
Long PV intervals may initiate an endless-loop Tachycardia

35. Wenckebach and MTR Atrial rate 160 140 120 100 80 60 80 100 120 140
Stimulated ventricular rate
160
140
TARP
120
= Max. Tracking Rate
100
Theoretically, you could limit the fall at 2:1 block by use of MTR. This method may be used in systems without rate modulation, but is, of course, seldom the optimal method. 80 60
Sensed Atrial Rate 80
100
120
140
160

36. Upper Rate Responses Fixed-ratio Block Wenckebach AMS AV Delay
constant
until DDI(R)
pacing
occurs at
the AMS
base rate
PV Delay
constant
AV Delay progressively lengthens
Pauses in pacing operation may be seen

37. 2:1 blocking Ex.: Shipped Settings PV Delay 150 ms PVARP 275 ms
Atrial rate
Stimulated ventricular rate
160
Ex.: Shipped Settings
PV Delay 150 ms
PVARP 275 ms
2:1-blockpoint 142 min-1
140
120
100
In shipped settings, the 2:1 block rate is quite low! This would affect pacing in normal, physiologic rate range of many patients and has to be dealt with. 80 60
Sensed Atrial Rate 80
100
120
140
160

38. Factors Limiting Upper RateV
TARP equals PV delay plus PVARP. This is the limiting factor when P-wave tracking.
PV Delay
PVARP
Programmed PV Delay
Rate Resp. AV/PV Delay
Shortest AV/PV Delay
Programmed PVARP
Rate Resp. PVARP/VRP
Shortest PVARP/VRP

39. Rate Responsive AV Delay
To mimic normal heart function
70 min-1
110 min-1
130 min-1
Spontaneous PR interval reduction
Tracking with RRAVD enabled
Rate responsive AV delay will increase the 2:1 block rate. It can be physiologic on exercise. RRAVD is mainly intended for AV block patients.

40. Rate Responsive AV/PV Delays and Shortest AV/PV Delay
200
150
100 50 90 95
100
110
105
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
Low, 1 ms min-1
Medium, 2 ms min-1
High, 3 ms min-1

41. Rate Responsive AV/PV Delays… … and Shortest AV/PV Delay
200
150
100 50 90 95
100
110
105
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
Low, 1 ms min-1
Medium, 2 ms min-1
High, 3 ms min-1

42. 2:1 blocking and RRAVD Ex.: Shipped Settings PV Delay 150 ms
Atrial rate
2:1 blocking and RRAVD
Stimulated ventricular rate
160
Ex.: Shipped Settings
PV Delay 150 ms
PVARP 275 ms
With RRAVD (Low, Medium and High)
140
120
100 80 60
Sensed Atrial Rate 80
100
120
140
160

43. Rate Responsive Refractory Periods
PVARP
Rate responsive refractory periods is another way of managing the 2:1 block point. This feature is intended mainly for patients with sinus node disease. This is because RRAVD would promote ventricular stimulation at higher rates, something you do not want in case of no AV block.
VRP
Low, 1 ms min-1
Medium, 2 ms min-1
High, 3 ms min-1

44. Rate Responsive Refractory Periods
PVARP
VRP
Low, 1 ms min-1
Medium, 2 ms min-1
High, 3 ms min-1

45. Rate Responsive Refractory Periods
PVARP
VRP
Low, 1 ms min-1
Medium, 2 ms min-1
High, 3 ms min-1

46. Rate Responsive Refractory Periods
PVARP
VRP
Low, 1 ms min-1
Medium, 2 ms min-1
High, 3 ms min-1

47. Pseudo Wenckebach Upper Rate Behaviour
Maximum tracking rate will limit the paced ventricular rate on tracking by producing a blocking similar to Wenckebach block.
MTR Intervall
MTR Intervall
MTR Intervall
MTR Intervall

48. 2:1 blocking and MTR
Atrial rate
Stimulated ventricular rate
160
140
= Max. Tracking Rate
Programmed MTR, too high. Will not limit the rate fall at 2:1 block rate.
120
100
In a DDDO system, programming MTR as high as possible will not limit the stimulated ventricular rate fall significantly. If 2:1 block rate is within the physiologic rate range of the patient, this is not a good programming. 80 60
Sensed Atrial Rate 80
100
120
140
160

49. 2:1 blocking Use of a well tailored
Atrial rate
Stimulated ventricular rate
160
140
= Max. Tracking Rate
= Max. Sensor Rate
120
= Sensor Indicated Rate
Use of a well tailored
sensor will relieve the problems of a high MTR
100
It is ok to programme high MTR if the sensor is ON and programmed slightly conservatively compared to the sinus node. Sensor Prediction Model is the perfect tool for this. 80 60
Sensed Atrial Rate 80
100
120
140
160

50. Summary
One to One tracking is the best upper rate behavior
When tracking at this rate is inappropriate, the device may be programmed to exhibit:
Fixed Ratio Block (Multiblock)
Wenckebach
RR AV delay – PVARP/VRP
DDIR
Auto Mode Switch

51. 2/1 block (mentioned on Merlin)
Summary
When programming
AV delay
PVARP
Max Tracking Rate
Remember
Wenckebach
AVD + PVARP < MTR
2/1 block (mentioned on Merlin)
AVD + PVARP = MTR

52. Merlin

53. Upper Rate Behavior
Questions