Rate Response Flashcards
What is the term for when a patient’s heart is unable to modulate/change the rate in response to increased activity or metabolic demand?
chronotropic incompetence
What is the purpose of Rate Response?
to modulate/increase the HR to meet metabolic demand d/t increases in activity
What are the 3 steps taken by the rate response feature when adjusting the patient’s HR?
- estimates metabolic need
- calculates pacing rate
- optimizes or adjusts according to sensed motion
How does the rate response feature estimate the metabolic needs of a patient?
- uses an accelerometer attached to the circuit board of the device
- flexing of accelerometer produces an electrical signal
- measures amplitude and frequency q2 seconds
- only measures signals above activity threshold
What is the nominal setting for the activity threshold value?
medium/low
What calculation is used to estimate the upper sensor rate?
(220 - pts age) x 80%
ex: (220 - 40y/o) x 80% = 144bpm
What effect does increasing the ADL or Exertion response value have?
- makes it harder for patient to increase HR
- increasing these values means more sensor counts are required to increase the HR
What does the Activity Acceleration value in the Rate Response feature do?
- determines how quickly the pacing rate increases to the target sensor rate at the onset of strenuous activity
What does the Activity Deceleration value in the Rate Response feature do?
- determines how quickly the pacing rate decreases to the target sensor rate when the patients activity stops
Which feature monitors and adjusts the ADL and Exertion rate response levels according to the patients activity?
Rate Profile Optimization
In which patient population(s) should Rate Profile Optimization be turn off?
- extremely sedentary or extremely active patients
- need to adjust rate response manually
How often does Rate Profile Optimization adjust rate response values?
once a day
What type of activity and how much time should a patient with an ADL response value of 3 spend at or near the ADL rate?
- moderately active
- 30 min
How much time should a patient with an ADL response value of 1 spend at or near the ADL rate?
-8 min
What type of activity and how much time should a patient with an ADL response value of 4 spend at or near the ADL rate?
- more active
- 60 min
How much time should a patient with an ADL response value of 5 spend at or near the ADL rate?
- 100 min
How much time should a patient with an ADL response value of 2 spend at or near the ADL rate?
- 15 min
How much time should a patient with an Exertion response value of 1 spend at or near the USR?
- 21 min
How much time should a patient with an Exertion response value of 2 spend at or near the USR?
- 21 min
How much time should a patient with an Exertion response value of 3 spend at or near the USR?
- 21 min
How frequent and how much time should a patient with an Exertion response value of 4 spend at or near the USR?
- more frequent
- 70 min
How much time should a patient with an Exertion response value of 4 spend at or near the USR?
- 133 min
What are the nominal settings for the ADL and Exertion response values?
3 for both
How does the rate profile optimization algorithm work?
- collects daily sensor rate profile and merges data into a long-term sensor rate profile
- compares daily and long-term Sensor Indicated Rate Profiles (SIRP) to the Target Rate Profile to assess the performance of the currently programmed values
- if SIRP = target profile or the daily and long-term SIRP contradict each other, NO rate adjustment will occur
What programming change should be made if the patient’s Sensor Rate profile is showing a higher percentage of time spent pacing than the target profile?
- meaning the patient’s HR is spending more time in the ADL or Exertional zones than recommended per the target rate profile
- program rate response to be less sensitive which adjusts the ADL and/or exertional setpoints to make it more difficult for the patient to reach the target profile rate
- slope becomes less steep and patient requires more aggressive stimulation to reach their target HR
What programming change should be made if the patient’s Sensor Rate profile is showing a lower percentage of time spent pacing than the target profile?
- meaning the patient’s HR is not spending as much time in the ADL or Exertional zones than recommended per the target rate profile
- program rate response to be more sensitive which adjusts the ADL and/or exertional setpoints to make it more easier for the patient to reach the target profile rate
- slope becomes steeper and patient reaches their target HR sooner with less stimulation
What are the smallest/largest values for both the ADL and UR setpoints in Rate Response?
- ADL: 5 - 80
- UR setpoint: 15 - 180
What does it mean when the ADL and UR setpoints are set to 5 and 15 at interrogation?
- pt is mostly sedentary and RPO has reduced the setpoints to the minimum settings to make it easier for the patient to reach their target HR
- change the Activity Threshold by one to make the sensor more sensitive and require less stimulation for activation
What is the difference between the UTR and the USR?
- UTR is the highest rate the PM will track the atrium and pace the ventricles
- USR is the highest rate, rate response will pace in response to physical activity
What shape does the ideal rate histogram show when evaluating rate response performance?
want the rate histogram to have a staircase like distribution/appearance
`What should be reviewed when evaluating Rate Response in a patient with a mix of pacing and sensing?
evaluate/review the Sensor Indicated Rate Profile for rate distribution (should look have staircase appearance)
`What should be reviewed when evaluating Rate Response in a patient is primarily paced?
evaluate/review the Rate Histogram for rate distribution (should look have staircase appearance)
How do you evaluate the activity threshold of a patient while in the clinic to determine the rate response setting that will not trigger rate response pacing at rest?
- have patient rest for about 10 min
- if HR is 50 bpm or greater, change the activity threshold to be less sensitive (low to med low)
- if pacing at or below the LR, change activity threshold to be more sensitive (med low to low)
- observe pt after change is made
What is the nominal ADL rate setting?
95 bpm
What are the 4 programing options for the activity threshold settings?
- low
- med/low
- med/high
- high
How long after implant of a transvenous pacemaker is rate response enabled and why?
- automatically enable 30 after implant d/t the implant detect algorithm
- rate response is one of 5 algorithms that won’t turn on until after implant detect is turned off or completes its polarity check 30 mins after implant
How long after implant of an ICD is rate response enabled and why?
rate response is automatically turned on once VF detection is programmed to On
What affect does increasing the ADL/UR setpoint value have?
increasing the setpoint will require more sensor counts to increase the HR to the target zones, meaning it will take more action/activity on the part of the patient to increase their HR
What happens to the activity slope when the setpoint value is increased?
- the slope becomes less steep, making it harder for the patient to reach the target HR zone
- requires more effort to increase the HR
What value determines the minimum number of sensor counts needed to reach the ADL rate?
the ADL setpoint
What value determines the minimum number of sensor counts needed to reach the USR?
the Exertion setpoint
