Rate Smoothing for Micra AV

The Rate Smoothing feature, in Micra™ AV Transcatheter Pacing System (TPS), is designed to improve AV synchrony during intermittent A4 undersensing. When undersensing occurs, the device will pace at the Rate Smoothing interval, which is based on the recent pacing history plus an offset. This provides pacing at the right time and increases the likelihood the device will track the next cycle.

This feature can be found in Micra™ AV Transcatheter Pacing System (TPS). Please go to manuals.medtronic.com or consult with your local Medtronic representative regarding device models available in your geography.

Rate Smoothing is nominally programmed On with a programmable Smoothing Delta value, nominally 100ms. Rate Smoothing is available in the programmed VDD mode and functions when the device is operating in the VDD mode.

 

 

To program this feature, go to Params -> Atrial Parameters -> Rate Smoothing

When Rate Smoothing is programmed to On, the device sets the Rate Smoothing pacing interval based on the recent pacing history plus an offset. This Rate Smoothing interval is bounded by the programmed Lower Rate. If no atrial contraction is sensed and the Rate Smoothing interval times out, the device will pace at this Rate Smoothing rate. Setting the Rate Smoothing interval based on the pacing history allows the device to predict and pace close to where the next atrial event is likely to occur. Adding the Rate Smoothing offset to the Rate Smoothing pacing interval allows tracking of the atrial rate in the presence of some sinus rate variation. The Rate Smoothing offset can be programmed via the Smoothing Delta.

 

 

  1. Appropriate atrial sensing with AV synchronous pacing
  2. Atrial undersense. Ventricular pace occurs at the Rate Smoothing interval, instead of Lower Rate (1200ms)
  3. Recovery of appropriate atrial sensing with AV synchronous pacing

Note: VE marker shown in the image above stand for “ventricular end” or the end of A1 – A3 ventricular-event signals.

References

Sources 

Micra™ AV MC1AVR1, Reference Manual

Last updated: 
23 Jan 2020