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Upper Rate Behavior

Upper Rate Behavior

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Upper Rate Behavior

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    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

    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

    14. Fixed-Ratio Block 2:1 Block (one v-paced event per two p-waves)

    15. Fixed-Ratio Block Calculation 60,000 / TARP: e.g. 60,000 / 440 ms = 136 BPM

    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

    18. 2:1 blocking 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.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.

    19. Upper Rate Responses Wenckebach

    20. Upper Rate Behavior Wenckebach block

    21. Do you remember?

    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

    24. Wenckebach behaviour

    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 Wenckebach response to increasing Atrial rates

    27. Wenckebach Example DDD MTR 100 bpm (600 ms) AV delay 150 ms PVARP 250 ms TARP 150 + 250 = 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 (600-400) PV intervals will vary from 150 - 350 ms

    28. Wenckebach Calculation to determine if a Wenckebach is present: Programmed MTR minus TARP In our example: 600 ms - 400 ms = 200 ms We have a 200 ms Wenckebach window

    29. Atrial Rate Continuum

    30. Wenckebach

    31. Pseudo Wenckebach - Upper Rate Behaviour

    32. Wenckebach

    33. Wenckebach

    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 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. 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.

    36. Upper Rate Responses

    37. 2:1 blocking 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.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.

    38. Factors Limiting Upper Rate TARP equals PV delay plus PVARP. This is the limiting factor when P-wave tracking. TARP equals PV delay plus PVARP. This is the limiting factor when P-wave tracking.

    39. Rate Responsive AV Delay 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. 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

    41. Rate Responsive AV/PV Delays and Shortest AV/PV Delay

    42. 2:1 blocking and RRAVD

    43. Rate Responsive Refractory Periods 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. 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.

    44. Rate Responsive Refractory Periods

    45. Rate Responsive Refractory Periods

    46. Rate Responsive Refractory Periods

    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.Maximum tracking rate will limit the paced ventricular rate on tracking by producing a blocking similar to Wenckebach block.

    48. 2:1 blocking and MTR 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.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.

    49. 2:1 blocking 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. 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.

    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. 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