Progressive Episode Therapies Feature
During an ongoing ventricular tachyarrhythmia episode, the ventricular rate may accelerate or decelerate, which can cause the device to redetect the episode as a different type of tachyarrhythmia. If this occurs, the device delivers the next available therapy programmed for the type of tachyarrhythmia that was redetected. In some cases, this can cause the therapies delivered later in an episode to be less aggressive than those delivered earlier in the same episode. For example, the device could detect an episode as VF, deliver a defibrillation therapy, redetect the episode as FVT, and then deliver an ATP therapy.
When the Progressive Episode Therapies feature is programmed On, the device skips therapies or modifies high-voltage energy levels to ensure that each therapy delivered during a ventricular tachyarrhythmia episode is at least as aggressive as the previous therapy.
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.
Progressive Episode Therapies is nominally Off and can be programmed to On.
To program this feature, go to Params -> VF Therapies -> Shared Settings.
Each time the device delivers a therapy during a ventricular tachyarrhythmia episode, Progressive Episode Therapies adjusts the therapies that are available if the episode is redetected. It makes three different kinds of adjustments.
First, the device does not deliver therapies programmed for slower tachyarrhythmia types for the remainder of the episode. Instead, it delivers the next therapy programmed for the fastest tachyarrhythmia type detected during the episode. For example, if the device detects VF and delivers a defibrillation therapy, it delivers only VF defibrillation therapies for the rest of the episode.
Second, if the device delivers a ventricular cardioversion therapy, it skips all ATP therapies for the remainder of the episode. For example, if the device detects a VT, delivers a cardioversion therapy, and redetects the episode as FVT, it skips any ATP therapies programmed for FVT. Instead, the device delivers the next cardioversion therapy programmed for FVT.
Finally, if the device delivers a ventricular cardioversion therapy, it adjusts the energy value for the next cardioversion or defibrillation therapy to be equal to or greater than the energy value of the last delivered therapy. For example, if the device detects a VT, delivers a 35 J cardioversion, and redetects the episode as FVT, the next cardioversion therapy will also deliver 35 J, even if the programmed value is 20 J.
- Progressive Episode Therapies operation does not cause the device to skip ATP During Charging™. However, if ATP Before Charging™ is enabled, the device skips the ATP sequence before charging, and only delivers an ATP sequence during charging.
- Evaluation of Progressive Episode Therapies – The episode text for a treated ventricular tachyarrhythmia episode lists all therapies the device delivered during the episode. If Progressive Episode Therapies is enabled, this fact is noted before the list of therapies (see below).
Episode text with Progressive Episode Therapies programmed to On:
Sources: Medtronic Protecta™ XT DR Clinician Manual; Medtronic Protecta™ XT CRT-D Clinician Manual.