2. AF Suppression™ Algorithm Overview
St. Jude Medical recently completed the ADOPT-A which yielded favorable results in support of the proprietary AF Suppression algorithm.
(Refer to bullets)

3. 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

4. AF Suppression, AFx
> 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

5. AF Suppression, AFx MSR AFx Intrinsic Rate Basic Rate
Searches will happen approximately 2-3 times a minute.
Basic Rate

6. AF Suppression, AFx
AFx
Overdrive: 10 min-1 at rate 60 min-1 and 5 min-1 at rate 150 min-1.

7. AF Suppression, AFx Search for intrinsic activity 67 66 65
Activity found (two P-waves) 64 65
Increase stimulation rate 74 AP AP AP AS AS AP AP AP VP
To apply overdrive, two P-waves has to be sensed, the second within 16 cycles from the first. VP VP VP VP VP VP VP VP

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

9. 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

10. AF Suppression™ Algorithm Overview

11. AF Suppression™ Algorithm Overview

12. 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

13. AF Suppression™ Algorithm Overview
Only 1 P-wave was seen. Therefore, NO Overdrive occurs
Start 16-cycle counter
End 16-cycle counter
AS AP AP AP AP AP AP AP AP AP AP AP AP AP AP AP AP
AS = P-wave
AP = Atrial pacing
Note: Notice how the algorithm starts with a “0” not a “1”

14. 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 AP AS
AS = P-wave
AP = Atrial pacing

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

16. 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

17. 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

18. 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

19. 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

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

21. 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

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

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

24. 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

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