Wavelet Flashcards
Is Wavelet applied at detection, redetect or both?
only at initial VT/VF detection or NID
How does the Wavelet algorithm collect a template?
- collects and compares 6 R-wave samples to the programmed threshold value
- device confirms template by comparing R waves q10 secs to the template
- need 70 out of 100 R-wave matches to confirm the template
- if unable to confirm, will restart the collection process
How often does the auto-collection feature of wavelet monitor/check R-waves to assess the quality of the stored template?
- assesses 100 R-waves q1000 secs
- if can’t get 70/100 R-wave matches, will recollect template
How many beats does the Wavelet feature evaluate to determine a match percentage?
- looks back 8 beats once NID is met
When will Wavelet withhold therapy?
- if at least 3 of the last 8 R-waves are a 70% or greater match with the store template
What will be seen in the channel marker if Wavelet is withholding therapy?
WV
What does a WV in the channel marker mean?
the Wavelet has withheld therapy
What does HT in the channel marker mean?
indicates the High Rate Timeout timer expired, wavelet and PR-Logic stopped withholding therapy and detection
Which EGM2 source does Wavelet use if RV Lead Noise is programmed ON?
CAN to RVcoil or RVcoil to SVC
What would you do if the Wavelet signal amplitude is too small at collection?
- try a changing EGM2 to a different source that does not include the CAN
- try changing the EGM2 range
What is the nominal setting for the PR-Logic/Wavelet High Rate Timeout?
45 seconds
Where is Wavelet programmed on the device?
under V. Detection
What is the fastest rate Wavelet will applied and what is the nominally setting?
SVT Limit at 260ms
How does the device determine if Wavelet can be applied once the VT/VF NID is met?
- the device looks back at the last 12 V-V intervals and determines a median ventricular cycle length
- Wavelet is applied if the cycle length is greater than the SVT limit
When collecting a Wavelet template, what is a possible solution if the Peak-Peak R-wave amplitudes are < 3mV on EGM2 and noise is seen?
change the EGM2 source
When collecting a Wavelet template, what is a possible solution if the EGM (QRS) signal is clipped or is signal is within 1mV of the EGM2 range?
increase the EGM2 range
When collecting a Wavelet template, what is a possible solution if the R-wave amplitude is too large at any range?
change the EGM source, then reassess beginning with a range of +/- 8 mV
Can Wavelet collect a template if the patient is pacing 100% of the time?
No, sensing of intrinsic R-waves is required
In single/dual chamber devices, is auto-collection for the Wavelet feature nominally on or off?
Nominally ON
In CRT-D devices, is auto-collection for the Wavelet feature nominally on or off?
- Nominally OFF
- need to manually collect since the device will be pacing 100% of the time
How long does it take for the device to confirm the Wavelet template after collection?
- at least 12 min
- longer if intrinsic rhythm has changed since collection
How long is the Wavelet auto-collect suspended for when any of the following occurs: tachy episode, system test, EP study, Emergency operation?
suspended for 1 hr after termination of the episode or completion of the test/procedure
For which patients do you have to manually collect a Wavelet template?
- pts with CRT-D devices
- pts who pace close to 100% of the time
At follow/up, how do you confirm that the Wavelet template is consistent with the patients sinus rhythm?
Click on the “SHOW Match Scores” on the Wavelet test screen and collect a new template if scores are lest then an 80% match
When will Wavelet evaluate the rhythm PR-Logic is also turned on?
- when PR-logic does not classify the rhythm as an SVT and withhold therapy
- ventricular ≤ atrial rate
