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Published byBryan McDaniel Modified over 3 years ago

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AF Suppression Algorithm Overview

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for internal use only 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 patients changing intrinsic atrial rate, resulting in constant atrial pacing

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for internal use only > 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

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for internal use only MSR Basic Rate AFx Intrinsic Rate AF Suppression, AFx

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for internal use only AF Suppression, AFx AFx

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for internal use only Search for intrinsic activity Activity found (two P-waves) 6465 Increase stimulation rate 74 AF Suppression, AFx ASAP AS AP VP

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for internal use only … and to programme: ON / OFF ! AF Suppression, AFx

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for internal use only 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

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for internal use only AF Suppression Algorithm Overview

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for internal use only AF Suppression Algorithm Overview

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for internal use only 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

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

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for internal use only AF Suppression Algorithm Overview AS AP AP AP AP AP AP AP AP AP AP AP AP AP AP AS Start 16-cycle counter 2 P-waves were seen therefore, Overdrive occurs Start Overdrive AS = P-wave AP = Atrial pacing

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for internal use only AS Overdrive Rate Pacing Rate 2 P-waves were seen therefore, Overdrive occurs AF Suppression Algorithm Overview

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for internal use only 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

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for internal use only 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

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for internal use only 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

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for internal use only AS Overdrive Rate Pacing Rate 2 P-waves were seen therefore, Overdrive occurs followed by Rate Recovery Pacing Rate AF Suppression Algorithm Overview Rate Recovery

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for internal use only AF Suppression Algorithm Overview What if there are additional P-waves sensed during the Overdrive portion?

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for internal use only 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

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for internal use only AS Overdrive Rate Pacing Rate AS Overdrive Rate AF Suppression Algorithm Overview Rate Recovery

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for internal use only AF Suppression Algorithm Overview What if 1 P-wave is sensed in the Rate Recovery portion?

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for internal use only 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

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for internal use only AS Overdrive Rate Pacing Rate AS Overdrive Rate Rate Recovery AF Suppression Algorithm Overview

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