MICRA TPS Flashcards
Is the Micra TPS MRI compatible?
yes, for 1.5T and 3T full body MRIs
What is the longevity (battery life) of the Micra TPS?
approximately 12 years
What is the minimum acceptable battery voltage require at implant of a Micra TPS?
at least 3.0 mV
What are the steps to the pre-op pre-program of the Micra TPS?
- interrogate to ensure battery voltage is at least 3.0mV
- switch mode to VVI
- set the date/time
- program pacing values
- switch to Device Off mode before implanting
- click on end session
What needs to be done to the introducer of a Micra TPS prior to use?
wet with NS to activate the hydrophilic coating
How many tines are required to be engaged or in position prior to conducting a pull and hold test of a Micra TPS?
at least 2 tines need to be engaged
What is the recommended R-wave amplitude for a Micra TPS at implant?
5mV ≤
What is the recommended impedance for a Micra TPS at implant?
400 - 1500 ohms
What is the recommended threshold for a Micra TPS at implant?
< 1.0 V
What mode is set when using a Micra TPS?
VVI
What are the 2 methods for conducting a threshold test on a Micra TPS?
- Capture Management (CM) (automated process)
- Amplitude decrement test (manual)
What is the first step in reposition a Micra TPS if unacceptable values result?
turn the device off
What solution is used to flush the delivery system of a Micra TPS prior to removing the tether (strings)?
heparinized saline to remove any formed blood clots
What should be done if resistance if felt when confirming free movement of the tether prior removal following deployment of a Micra TPS?
flush the delivery system with heparinized saline
What technique is used when inserted/placing a Micra TPS?
- Seldinger Technique
- use of a guidewire and dilation cannula to place a catheter (same used for central line placement)
What feature adjusts the patient’s rate response to ensure that it remains appropriate for the full range of patient activities?
Rate Profile Optimization (RPO)
What is does the Rate Profile Optimization (RPO) feature do when programmed on a Micra TPS?
automatically adjusts the patient’s rate response to ensure that it remains appropriate for the full range of patient activities
How does the accelerometer in the Micra TPS tell the difference between the normal resting heart motion and the higher levels of motion that occur during exercise?
- Lower Rate Setpoint feature sets a unique baseline to differentiate normal heart motion at rest versus that occurring with increased activity
What type of accelerometer is contained in the Micra TPS and why?
- a 3 axis accelerometer compared to a single axis in traditional IPG
- to account for the different angle positions the device may be in at implant
When is the Activity Vector Test (AVT) performed after a Micra implant?
- prior to discharge after placement
- when there is concern about adequate rate response
The Micra TPS should be in what mode when performing an Activity Vector Test?
VVIR
What are the main purposes of the Activity Vector Test?
- to set the rate response setpoints
- to determine the activity vector (1 or 3) where rate response performs the best
What should the lower rate setpoint be set to when manually programming setpoints on a Micra TPS following an Activity Vector Test?
set LR to 2 counts above the highest peak counts while at rest
What should the activities of daily living (ADL) setpoint be set to when performing manual programming on a Micra TPS following an Activity Vector Test?
set ADL setpoint to the value of the highest peaks while walking
What equation is used to manually program the upper rate setpoint on a Micra TPS following an Activity Vector Test?
UR = 1.5x (ADL setpoint - LR setpoint) + ADL
What are the inner and outer diameters for the MICRA introducer?
- inner = 23FR
- outer = 27FR
How long is the MICRA introducer?
56cm in length
What type and size of guidewire should be used to when inserting the MICRA introducer?
a superstiff 0.035mm guidewire
What should be done if resistance is felt when confirming free movement of the tether after MICRA deployment?
flush the delivery system
How often does capture management conduct threshold search for the Micra?
a pacing threshold search is done everyday and looks for an evoke response
What is the threshold safety margin during the Acute phase (first 112 days) with a Micra?
the highest pacing threshold in the past 2 weeks + 1.5V
What is the threshold safety margin during the Chronic phase with a Micra?
the highest pacing threshold in the past 2 weeks + 0.5V
What is the nominal pulse width value on the Micra?
0.24ms, but can be programmed to 0.4ms
How often does capture management conduct a threshold confirmation test when adaptive mode is programmed on a Micra?
- done hourly
- confirmation is done with a pulse 0.125 V above the measured threshold
At what voltage will the Micra PM automatically switch to OOO?
when the battery voltage gets to 2.5 V will switch to OOO, but can support telemetry for about 1yr after
What does the A1 window represent when conducting a MAM test on a Micra AV?
- start of the ventricular systole and AV valve (mitral/tricuspid) closure
- result of QRS
What does the A2 window represent when conducting a MAM test on a Micra AV?
- end of ventricular systole and semilunar valve (aortic/pulmonic) closure
- near or end of T-wave
What does the A3 window represent when conducting a MAM test on a Micra AV?
- diastole
- corresponds to E-wave on the doppler echo
What does the A4 window represent when conducting a MAM test on a Micra AV?
- atrial systole or contraction
- window starts at beginning of the P-wave
- corresponds to A-wave on doppler echo
What does the Micra AV do to the A1 and A2 signals?
blanks them by having them fall into PVAB
What does VE represent on a Micra AV egm?
it marks the end of the A3 window
When does the A4 signal occur after the P-wave?
appx 100ms, marked by an AM on the egm
What does AM represent on a Micra AV egm?
- stands for Atrial Mechanical
- marks sensing of A4 signal
At what atrial rate will a Micra AV lose the ability to track atrial activity?
atrial rate > 100bpm
What is the AM-VP interval on a Micra AV?
- starts with AM marker
- programmed short due to AM sensing occurring appx 100ms after the P-wave
What is the nominal AM-VP interval on a Micra AV?
20ms
What Micra AV feature switches to VVI+ at 40bpm if AV conduction is present?
AV Conduction Mode Switch
How does the Micra AV perform conduction checks?
- does VVI 40 sensing test
- starts 1 min after VDD mode is programmed and doubles time up to 8hrs if conduction is present
- then does the check q8hrs
What is/are indications for a Micra AV?
pts with AVB only and adequate sinus rates
What is/are indications for a Micra VR?
pts with AVB and AF
When should the AV conduction mode switch feature be turned off on a Micra AV?
in patients with permanent AV block and junctional or ventricular escape (IVR) greater than 40 bpm
When would the Micra AV switch from VVI+ 40 to back to VDD mode after a mode switch?
if 2 of 4 beats are VP at 40bpm
What does the activity mode-switch feature do on a Micra AV?
switches to VDIR mode if exercise is detected and the current rate is low
Which feature should be turned off if Rate Response is not appropriate for the patient?
turn off activity mode switch
What happens when a Micra reaches RRT?
functions normally for 90 days, no changes are made
What happens when a Micra reaches ERI?
mode changes to VVI at 65 bpm but can be reprogrammed if needed
How long after a Micra reaches RRT will ERI occur?
90 days after RRT
What happens to the Micra at the end of service (EOS)?
device permanently turns off pacing operations
When performing a MAM test what mode should be used if atrial undersensing (p-waves but no AM marker) occurs?
perform test in VDD at 50bpm
When performing a MAM test what mode should be used if atrial oversensing (AM marker but no p-waves) occurs?
perform test in VDI at 50bpm