From Ask Dr Wiki
Guidant
Sequence for Tachycardia Detection
- Initial Detection 8 of 10 intervals must be within the VT Zone
- Duration 6 of 10 must continue to be in th VT Zone to remain satisfied
- Charge 6 of 10 (remain satisfied)
- Reconfig (2 of 3)
- Shock
- Redetection 8 of 10
Initial VT Detection Enhancements
Available in VT-1 Zone
- V rate > A rate(On/Off)
- A fib rate threshold (200 bpm; range 200-400 bpm). Each atrial interval is compared to the programmed AF rate threshold and classified as faster or slower. If 6 of the last 10 atrial intervals are faster than than the AF rate threshold then AF is present and therapy in inhibited. If 4/10 remains greater than the AF rate, AF still present.
- Stability-Inhibit(10 ms in dual chamber/ 30 ms in single chamber; range 6-120 ms). It evaluates cycle length variability to differentiate ventricular rhythms from unstable rhythms. If the value is greater than 10 ms or the programmed value the device with inhibit. If it is less than 10 ms the device will deliver therapy.
- Onset (Default 9%; range 9-50%), used to differentiate between monomorphic VT and sinus activity related to exercise. It evaluates how abruptly the cycle length changes from a normal rhythm to a rapid rhythm. If the measured value is more than 9% or the programmed value the device will deliver therapy if it is less than 9% or the programmed value it will inhibit.
- Sustained Rate Duration (30 seconds; 10 sec- 60 minutes)
VT Zone
- Stability-Accelerate (6-120ms). If the measured value is greater than the threhold it skips remaining ATP therapy and initiates a shock.
