Pacemaker main features/algorithms Flashcards
What Boston Scientific algorithms to reduce RV pacing do you know? How do they work?
Search AV + :promotes intrinsic AV by periodically extending the Av delay to the programmed AV Search + value and if a V-sense detected within 8 cycle search ventricular hysteresis (VS-Hy) continues and if VS-Hy >=25 beats the device switches to AAI with back up VVI mode (RythmIQ); if no intrinsic conduction is detected within the 8 cycle search period or 3 out of last 10 beats are VP the device remains in DDD mode for another certain amount of intervals (Search interval: number of intervals before Search AV delay occurs - can be programmed from 32-1024 intv). Therefore Search AV + works in combination with RythmIQ
RythmIQ (on its own):
- device works in AAI(R) at lower rate and/or sensor indicated rate
- device provides back up VVI pacing at a rate 15 beats slower than the programmed LRL (but limited to no slower than 30 bpm and no faster than 60 bpm)
- if 3 slow ventricular beats are detected in a 11 beats window the device switches to DDD(R) mode
- this algorithm is nominally OFF
Rate hysteresis:
Search hysteresis: the device will lower the pacing rate by the hysteresis offset (programmed) for up to 8 cardiac cycles. It intrinsic activity is sensed during the search period, rate hysteresis will remain active until atrial paced event occurs at the hysteresis offset rate.
Hysteresis offset: the minimum rate below LRL that the device with allow the intrinsic rate to drop to
What Medtronic RV pacing minimizing algorithms do you know? How do they work?
Managed Ventricular Pacing: the device works in AAI(R) operation while monitoring AV conduction. The device performs periodic one-cycle checks for AV conduction. The first check for AV conduction occurs after 1 min, then after 2min, 4min, 8min up to 16 hr and then remains at 16 hr thereafter. If the device operates in AAI(R) and upon AV conduction detects 2 consecutive dropped P waves, it provides back up VVI pacing at half the LRL + 80 msec for two consecutive beats then the device switches to DDD(R) mode. After 1min the device checks for AV conduction again.
Search AV + : the device assesses 16 AV conduction intervals and determines if the 8 or more VS are within 15 ms of the schedules VP, the PAV and SAV are extended by 62 ms to promote intrinsic conduction. If 8 or more VS events (within the last 16 intervals) occur 55 msec before the scheduled VP, PAV and SAV are shortened by 8 msec to limit long AV delays if VP is needed.
What Abbott/St. Jude RV pacing minimizing algorithm do you know? How does it work?
Ventricular Intrinsic Preference: corresponds to AV delay hysteresis
- the algorithms searches for intrinsic conduction by extending the AV interval (programmable number) for a certain number of intervals. The search time is also programmable.
Rate hysteresis: feature that allows atrial rate drop in DDD and ventricular rate drop in VVI mode. The device allows the intrinsic rate to drop to the programmed rate hysteresis rate. If search is enabled it periodically searches for intrinsic activity.
How does sudden brady response work in Boston Scientific?
Only available in DDD(R) modes. Designed to respond to sudden decrease in atrial rate by applying pacing at an elevated rate. Indicated in patient with neurocardiogenic syncope.
How does Rate Drop Response algorithm work in Medtronic?
Two methods to activate the algorithm: monitor for significant rate drop or monitor for atrial pacing at LRL or both.
How does CLS algorithm in Biotronik work?
How does atrial tachy response (Boston Scientific) work?
ATR markers on EGM - ATR atrial EGM
Ventricular fallback pacing - VP-FB
How does AMS work in Abbott?
How does Mode Switch work in Medtronic?
