Abbott / St Jude Assurity Pacemaker - A.Cap Confirm Setting

Wondering if anyone can add any detail to my basic knowledge of the Automatic.Atrial Capture Confirm (A.Cap Confirm) setting on the Abbott Assurity Pacemaker? (There is also an automatic ventricular capture setting - I forget the name of it - but this is not programmed. Not sure why. I receive less than 5% vp.)

I have found an online explanation of the setting - but it's complicated. I've grasped bits of it and worked out others, but I particularly need to know a) which other settings on the device it is altering automatically and b) how the search interval interacts with A.Cap Confirm and c) the search interval options for A.Cap Confirm (8hrs / 12 hrs I think. Are there any longer ones?)

Sorry for all the Qs, but it would really help if anyone is skilled enough to explain this setting to me in laymans terms rather than referring me to links / references which I have already tried to interpret myself ... and mainly failed! 

Thanks in advance.






by PacedNRunning - 2023-01-15 19:09:35

Automatic capture is basically a threshold check. Its the same threshold check they do in office interrogations. It's determining the amount of energy to cause the heart to contract when a pacing stimulus is sent. It allows the device to use the Lowest amount of energy vs having it off will use higher energy. When they have it off they have to set the energy higher to keep us safe because our thresholds can change day to day. I have my A lead off and my V lead on. The A is off because it makes my whole PM jump. Plus the amount of energy it would set is higher than just setting a fixed amount. The V lead I feel too but it's on to save battery. I'm using my battery fast. 
I'm not sure how frequently Abbott can make it. Mine is every 21 hours and I feel every single one that isn't when I'm sleeping. 

Thank you PacedNRunning

by Penguin - 2023-01-15 20:38:58

Thank you very much for this. I really appreciate it!

I'll digest your response and may revert back with a few more Q's if I may? 

In the meantime would you happen to know how I might feel if no search interval is set for A.Cap Confirm? Seems to have disappeared on the printout...strange! 



Q's Re: Sensitivity, Pulse Amplitude, Capture/Sense / Lead impedance Results

by Penguin - 2023-01-16 10:26:11

Hi again, 

I have looked at two sets of clinic Test Results - A) in July and B) in August. They are one month apart and show test results for Capture, Sense and Impedance (A&V) with and without A.Cap Confirm in place. 

A) July A.Cap Confirm was programmed at this apptment and clinic test results (presumably before A.Cap Confirm was programmed) showed: 

A:  Capture: 0.5V @ 0.4ms   Sense 1.6mV  Impedance 460 ohms  Auto

V: Capture: 1.5V @ 0.8ms     Sense 1.8mV      Impedance 340 ohms Auto

A.Pulse amplitude was lowered from 1.75V to 1.5V at this session and V.Pulse amplitude left at 2.0V

B) August with A.Cap Confirm in place results showed : 

A: Capture 0.625V @ 0.4ms  Sense 2.7mV Auto   Impedance 460 ohms  Auto

V:  Capture Not Performed *   Sense 2.3mV  Auto     Impedance 350 ohms Auto

* Don't know why Capture test wasn't performed. Any ideas? 

A.Pulse Amplitude lowered (automatically) from 1.75V to 1.625V 


Sensitivity has been set to (Auto) since implantation. I've not had this setting before. Might be an obvious Q. but would you happen to know what it does and whether or not it is affected by A.Cap Confirm? 


A cap confirmed

by PacedNRunning - 2023-01-17 03:00:44

A cap confirmed is just your auto threshold daily test. It's the results from the last test. My guess is they turned off the V lead due to threshold being 1.5@0.8. With  my device it won't do auto if it's higher than 0.4ms and yours in the V is So this could be why it's off. 

Sensitivity and auto cap are 2 separate functions. The sensitivity is like the fence. The devices sees what is over the fence. If it's under the fence line, the device doesn't see it. It will only see those things above the fence line. This is so the device only sees true instrinsic beats and ignores noise from muscle etc. It's an auto because daily checks will set it automatically based on measure p and R waves. 

hope that helps 

Thanks Again

by Penguin - 2023-01-17 07:05:12


Yes it does help thank you and I can take it from here and ask more informed Q's perhaps.

You've explained sensitivity settings and how they relate to p and R wave measurements too, which I didn't know before.

I really appreciate your time.

Best wishes.


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