Rate Adaptive AV (RAAV) Feature

In the normal heart, AV conduction times tend to shorten as the heart rate increases and to lengthen as the heart rate decreases. The Rate Adaptive AV (RAAV) feature mimics this physiologic response.

This feature can be found in some Medtronic Pacemaker, ICD, CRT-P, and CRT-D devices. Please go to manuals.medtronic.com or consult with your local Medtronic representative regarding device models available in your geography.

To program this feature in pacemakers, go to Params -> Intrinsic / AV -> Intrinsic Activation - > Rate Adaptive AV.

To program this feature in ICDs, go to Params -> Pacing -> SAV… or PAV…

Programming for Adapta™ DR, Versa™ DR, Sensia™ DR Pacemakers

RAAV is nominally "Off".  However, it is available when the device is operating in DDDR, DDD, DDIR, DVIR, DOOR, VDD modes.

Programmable parameters for this feature include (nominal settings are shown in image above):

  • Start Rate – Shortening SAV and PAV intervals begins at this rate.
  • Stop Rate – Shortest SAV and PAV occur at this rate and at all rates above the stop rate, up to the upper rate limits.
  • Maximum Offset – Maximum amount of time (in ms) by which the SAV and PAV intervals can be shortened. The PAV minus the Maximum Offset gives the shortest PAV interval at the Stop Rate (e.g., 200 ms - 100 ms = 100 ms).  This parameter is present when the individual Minimum PAV and SAV parameters are not provided.

RAAV can be enabled while Search AV™+ is enabled. Search AV+ will operate using the AV intervals determined by RAAV rather than the programmed AV intervals.

 

Programming for ICDs, CRTs, Advisa DR MRI™, Revo™ MRI, and EnRhythm™ MRI

CRT-D and CRT-P devices: RAAV is nominally “On”. However, in devices where AdaptivCRT™ is available and is nominally “On”, RAAV does not apply since AdaptivCRT adjusts the AV parameter values. RAAV is programmable if AdaptivCRT is programmed to “Nonadaptive”.

Programmable parameters for this feature include (nominal settings are shown in image above):

  • Start Rate – Shortening of SAV and PAV intervals begins at this rate.
  • Stop Rate – Shortest SAV and PAV intervals occur at this rate and at all rates above the stop rate, up to the upper rate limits.
  • Minimum PAV – Shortest allowable Paced AV interval; used at or above the Stop Rate
  • Minimum SAV – Shortest allowable Sensed AV interval; used at or above the Stop Rate

When RAAV is programmed On, the device shortens AV intervals for atrial rates within the programmed Start Rate and Stop Rate. The Start Rate determines the heart rate at which the AV intervals begin to shorten. The Stop Rate determines the heart rate at which Minimum PAV intervals and Minimum SAV intervals are applied. This feature provides increased opportunity for atrial sensing, as follows:

  • Shortened SAV intervals increase the tracking range at fast atrial rates by shortening the total atrial refractory period (TARP) and increasing the 2:1 block rate.
  • Shortened PAV intervals lengthen the atrial sensing window of the VA interval at higher sensor-driven rates.

Adapta™ DR, Versa™ DR, Sensia™ DR Pacemaker Operation

 

ICD, CRT, Advisa DR MRI™, Rev™ MRI, and EnRhythm™ DR Operation

Considerations:

If RAAV is activated for a sick sinus syndrome patient who has AV conduction, consider the following:

  • The rate at which AV conduction is lost should not be too low (i.e., below 90 bpm).
  • Review of the AV Conduction Histogram diagnostic data may aid in appropriate programming of Start Rate and Stop Rate to maintain AV conduction as long as possible.
  • RAAV can be used in combination with Automatic PVARP to better manage total atrial refractory periods and upper tracking rate behavior in patients with AV block.

References

Sources: Medtronic Adapta/Versa/Sensia Reference Guide; Medtronic Consulta CRT-P Clinician Manual;Medtronic Protecta XT DR Clinician Manual; Medtronic Protecta XT CRT-D Clinician Manual; Viva/Viva Quad, Brava/Brava Quad CRT-D.

Last updated: 
19 Feb 2015