Medtronic PROTECTA XT DR D314DRG, Clinician Manual

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9.2 Treating VT and FVT episodes with antitachycardia
pacing therapies
The device detects sustained ventricular tachycardia as a ventricular tachycardia (VT) or
fast ventricular tachycardia (FVT) episode. Treatments for these episodes are intended to
interrupt the ventricular tachycardia and restore the patient’s normal sinus rhythm. Pacing
therapy can be a treatment option for terminating a VT or FVT episode that may not require
high-voltage therapy.
9.2.1 System solution: ventricular antitachycardia pacing therapies
The device can respond to a VT or FVT episode by delivering ventricular antitachycardia
pacing (ATP) therapies to the patient’s heart. Ventricular ATP therapies are designed to
interrupt the VT or FVT reentrant activation pattern and restore the patient’s normal sinus
rhythm. ATP therapies deliver pacing pulses, instead of high-voltage shocks delivered in
cardioversion therapy.
For related information, refer to Section 8.2, “Detecting ventricular tachyarrhythmias”,
page 304, and Section 9.3, “Treating VT and FVT with ventricular cardioversion”,
page 380.
9.2.2 Operation of ventricular ATP therapies
The device can deliver up to 6 therapies to treat a VT or FVT episode. You can program the
device to deliver ATP therapies before delivering the first cardioversion therapy for each
type of episode. This may allow the device to terminate a ventricular tachycardia episode
using an ATP therapy, delivering cardioversion therapy only if the ATP therapy is
unsuccessful.
ATP therapy options are Burst, Ramp, and Ramp+ pacing, each with a programmable
number of sequences. When a VT or FVT episode is detected and the first programmed
therapy is an ATP therapy, the device delivers the first sequence of the ATP therapy. After
the first ATP sequence, it continues to monitor for the presence of the ventricular tachycardia
episode. If the device redetects the ventricular tachycardia episode, it delivers the next
sequence and repeats this cycle until the episode is terminated or all sequences in the
therapy are exhausted.
If all sequences in an ATP therapy are unsuccessful, the device starts delivering the next
ATP or cardioversion therapy. If it detects that the current VT episode has accelerated (by
at least 60 ms) or redetects the VT as FVT, the device skips the remaining sequences of an
ATP therapy and starts the next programmed therapy for the episode.
Medtronic PROTECTA™ XT DR D314DRG
368 Clinician Manual