Programmable parameters

VIP is nominally programmed OFF.

Three parameters are programmable in the VIP algorithm:

  • VIP Extension corresponding to the extension of the AV delay that is applied to the programmed AV delay: Off, 50, 75, 100, 125, 150, 160, 170, 180, 190 and 200 ms
  • Search interval corresponding to the time interval between each intrinsic conduction search: 30 seconds, 1, 3, 5, 10 or 30 minutes
  • Search cycles corresponding to the number of consecutive cycles with prolonged AV delay during which the search for intrinsic conduction occurs: 1, 2 or 3 cycles

The AV delay cannot be longer than 450 ms.

 

VIP feature programmability

 

 

 Activation and deactivation of the VIP algorithm

When programmed ON, the algorithm is activated in 2 conditions:

  • one intrinsic R-wave is sensed during a search interval
  • 3 consecutive sensed R-waves occur outside a search interval (whatever the number of programmed Search Cycles)

The algorithm is deactivated when:

  • the number of consecutive paced ventricular cycles is equal to the programmed number of Search Cycles (for example, 2 consecutive AP/VP or AS/VP cycles with Search cycles programmed at 2)

VIP suspends operation:

  • when atrial intrinsic rate or sensor indicated-rate is ≥ 110 bpm
  • during a capture or sense test
  • when mode-switching occurs

 

Examples

Example 1: the device extends the AV Delay by 160 ms searching for R-waves for up to 3 cycles. Intrinsic ventricular activation and the AV delay remains at the lengthened value.

Example 2: the device extends the AV Delay by 160 ms searching for R-waves for up to 3 cycles. No R-waves found within 3 cycles; the AV Delay returns to the programmed value.

Example 3: the VIP is activated following 3 R-waves detected outside a search interval. The VIP annotation appears after detection of 3 R-waves.

 

The VIP is deactivated after 3 consecutive AP-VP cycles with prolonged AV delay (344 ms); the AV delay remains extended with ventricular pacing for the number of programmed Cycle Count, 3 in this example, before it returns to the programmed AV delay.

Evaluating diagnostics

  • heart rate histograms evaluate the percent of VP
  • AV conduction counts determine the amount of VS

 

There is no specific mode per se to reduce the percentage of unnecessary right ventricular pacing in Abbott pacemakers.

  • the VIP algorithm corresponds to an AV delay hysteresis
  • the AV delay is prolonged over a limited number of intervals to promote the return of intrinsic conduction
  • at the end of the prolonged AV period, if no ventricular event has occurred, ventricular pacing is delivered

Activation du VIP

Recherche d’une conduction spontanée avec allongement temporaire du délai AV;

pm19_situation23.png

On voit dans cet exemple, la présence d’une onde R les 3 intervalles avec délai AV prolongé; le dispositif continue à fonctionner avec un délai AV long;

Désactivation du VIP

pm19_situation24.png

Dans cet exemple, la conduction atrio-ventriculaire s'altère avec présence de 3 ventricules stimulés malgré un délai AV long (350 ms) entrainant un retour à la programmation avec un délai AV plus court (220 ms);

VIP (Ventricular Intrinsic Preference – Abbott)

3 paramètres peuvent être programmés :

  • l’Extension VIP™ qui correspond à l'extension du délai AV qui est appliquée au délai AV programmé (stimulé ou détecté) pour rechercher une conduction spontanée
     
  • l’Intervalle de recherche qui correspond à l'intervalle de temps entre chaque recherche de conduction spontanée (30 secondes, 1, 3, 5, 10 ou 30 minutes)
     
  • le nombre de cycles qui correspond au nombre de cycles consécutifs avec délai AV prolongé durant lesquels la recherche d'une conduction spontané se produit (1, 2 ou 3 cycles)

pm19_situation25.png

Il est possible de visualiser l'histogramme de conduction atrio-ventriculaire dans les mémoires du stimulateur.

pm19_situation26.png

Il est également possible de programmer une alerte spécifique de télémédecine quand le pourcentage de stimulation ventriculaire dépasse un seuil programmable.

pm19_situation27.png