ChargeSaver/Switchback Feature

If the ChargeSaver option is programmed to On, the device can automatically switch from ATP During Charging operation to ATP Before Charging operation. This change occurs when ATP has successfully terminated the detected tachyarrhythmia on a programmable number of consecutive attempts during charging.

Switchback is a nonprogrammable feature that allows the device to automatically switch from ATP Before Charging operation to ATP During Charging operation. This change occurs if ATP Before Charging fails to terminate the detected tachyarrhythmia on two consecutive attempts.

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

ChargeSaver is programmed On nominally. One success of ATP During Charging will automatically switch the therapy to ATP Before Charging. Switchback is a nonprogrammable feature that is automatically on when ATP Before Charging is programmed On. Other programming options are ChargeSaver Off and number of consecutive ATP successes needed to switch (1, 2, 3, 4, 6, 8, 10).

To program these features, go to Params -> VF Therapies -> ATP.

ATP During Charging features a suite of algorithms that make it adaptable to the patient’s rhythm. If the ChargeSaver feature is programmed On and if ATP is successful for a programmed number of episodes, nominally one episode, the device will switch to ATP Before Charging. By switching to ATP Before Charging, the device can deliver one round of ATP before it starts to charge. If that ATP is successful, then the device does not have to charge, which saves battery longevity.1 If the ATP is unsuccessful, the device redetects the arrhythmia and delivers another round of ATP while it charges up to deliver a shock. For patients with multiple fast VTs that are amenable to ATP therapy, ATP Before Charging can save battery life effectively.1 However, there will be a longer delay to therapy when compared to ATP During Charging therapy.

The ATP During Charging suite also has a nonprogrammable feature called Switchback. This feature monitors the performance of ATP Before Charging and changes the programmed therapy to ATP During Charging if there are 2 consecutive episodes that fail to terminate with ATP. This automatic feature reduces the time to shock when the patient’s history suggests that the arrhythmia may not be amenable to pace-termination.

* Programmable (nominally set to one)

The example below displays a FVT terminated successfully with ATP During Charging. The EGM shows VF detection and ATP delivered during charging. The FVT is not terminated immediately after the ATP is delivered, but is terminated before a shock is delivered. The observation window shown on the Quick Look™ II Screen displays the device switched to ATP Before Charging due to 1 success of ATP During Charging. This is the result of ChargeSaver.

References

  1. Medtronic Protecta XT DR Clinician Manual.

Sources: Medtronic Protecta XT DR Clinician Manual; Medtronic Protecta XT CRT-D Clinician Manual.

Last updated: 
03 Apr 2013