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AF Suppression ™

AF Suppression ™. Algorithm Overview. AF Suppression ™ Algorithm Overview. The goal is to keep atrial arrhythmias from occurring Prevention of atrial fibrillation A fib begets A fib!

thane-mccullough
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AF Suppression ™

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  1. AF Suppression™ Algorithm Overview

  2. AF Suppression™ Algorithm Overview • The goal is to keep atrial arrhythmias from occurring • Prevention of atrial fibrillation • A fib begets A fib! • Solution: An algorithm designed to keep the atrial pacing rate just above the patient’s changing intrinsic atrial rate, resulting in constant atrial pacing

  3. > 90%Atrial Pacing AFx ensures a high percentage of atrial stimulation at a rate following the patients natural circadian variations, thereby maintaining control of the atrium, reducing ectopy, and suppressing atrial tachyarrhythmias AF Suppression, AFx

  4. AF Suppression, AFx MSR AFx Intrinsic Rate Basic Rate

  5. AFx AF Suppression, AFx

  6. Search for intrinsic activity Activity found(two P-waves) Increase stimulation rate 67 66 65 64 65 74 74 74 74 AF Suppression, AFx AP AS AS AP AP AP AP AP VP VP VP VP VP VP VP VP VP

  7. … and to programme: ON / OFF AF Suppression, AFx !

  8. AF Suppression™ Algorithm Overview • Programmable: • ON • OFF (nominal) • Screen: Parameters-Brady, AT/AF Detection & Response • Only available in the following modes • DDD/R • AAI/R

  9. AF Suppression™ Algorithm Overview

  10. AF Suppression™ Algorithm Overview

  11. AF Suppression™ Algorithm Overview • When the algorithm is activated, the device looks for • 2 P-waves within 16 cycles • Only P-waves in the alert period will be used • If 2 P-waves within 16 cycles are seen, the device will increase the atrial pacing rate

  12. AF Suppression™ Algorithm Overview Only 1 P-wave was seen. Therefore, NO Overdrive occurs Start 16-cycle counter End 16-cycle counter ASAP AP AP AP AP AP AP AP AP AP AP AP AP AP AP AP 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 AS= P-wave AP = Atrial pacing Note: Notice how the algorithm starts with a “0” not a “1”

  13. AF Suppression™ Algorithm Overview 2 P-waves were seen therefore, Overdrive occurs Start 16-cycle counter Start Overdrive AS AP AP AP AP AP AP AP AP AP AP AP AP AP APAS 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 AS= P-wave AP = Atrial pacing

  14. AF Suppression™ Algorithm Overview 2 P-waves were seen therefore, Overdrive occurs Overdrive Rate Pacing Rate AS AS

  15. AF Suppression™ Algorithm Overview • A look-up table within the device determines the Overdrive rate • The current atrial pacing rate is used to determine the increase in atrial rate • The Maximum AF Suppression rate is the maximum rate for atrial overdrive pacing when AF Suppression is programmed on

  16. AF Suppression™ Algorithm Overview • Once the atrial Overdrive rate is determined, the device will pace at this rate for a programmable number of cycles • 15 (nominal), 20, 25, 30, 35 or 40 cycles • When AF suppression is programmed ON, the Overdrive Pacing Cycles is the only programmable parameter • Cycle count of 15 was programmed most often during the Adopt-A clinical trial

  17. AF Suppression™ Algorithm Overview • Once the number of Overdrive cycles has been completed the Rate Recovery phase will start • If the Overdrive rate is  100 ppm - 12 ms will be added to each cycle, resulting in a lower rate • If the Overdrive rate is >100 ppm - 8 ms will be added to each cycle, resulting in a lower rate

  18. AF Suppression™ Algorithm Overview 2 P-waves were seen therefore, Overdrive occurs followed by Rate Recovery Overdrive Rate Rate Recovery Pacing Rate Pacing Rate AS AS

  19. AF Suppression™ Algorithm Overview • What if there are additional P-waves sensed during the Overdrive portion?

  20. AF Suppression™ Algorithm Overview • If 1 P-wave is sensed during the Overdrive portion, the 16 cycle counter will start • If 2 P-waves are sensed within 16 cycles, the device will increase the atrial rate and Overdrive will start

  21. AF Suppression™ Algorithm Overview Overdrive Rate Overdrive Rate Rate Recovery AS AS Pacing Rate Pacing Rate AS AS

  22. AF Suppression™ Algorithm Overview • What if 1 P-wave is sensed in the Rate Recovery portion?

  23. AF Suppression™ Algorithm Overview • If 1 P-wave is sensed during the Rate Recovery portion, the 16 cycle counter will start • If 2 P-waves are sensed within 16 cycles, the device will increase the atrial rate and Overdrive will start

  24. AF Suppression™ Algorithm Overview Overdrive Rate Overdrive Rate Rate Recovery AS AS Rate Recovery Pacing Rate Pacing Rate AS AS

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