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)

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

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

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

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

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

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

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

AF Suppression™ Algorithm Overview

AF Suppression™ Algorithm Overview

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

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 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”

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 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 AS = P-wave AP = Atrial pacing

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

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

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

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

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

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

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

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

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

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

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