Ventricular Detections Flashcards
Which counter does the device use to detect VT?
- Consecutive counter
- a VS will reset the consecutive counter
What happens to the VT counter do if an FS (fast sense) occurs?
VT counter holds at the current number
What counter is used to detect VF?
A probabilistic counter, allows for a 25% drop out d/t irregularity in R-wave sensing during VF
How is the combined counter turned on?
Automatically when both the VT and VF detections are ON
Explain the Combined Count “6,7,8 rule”?
- combined count is activated when VF counter = 6
- new CC detection VF NID is 7/6th the original VF NID
- ex: VF NID = 12/16; CC NID = 7/6 x 12 = 14/16
- CC looks back 8 intervals, if 1 is FS, then detection is met and therapy will be provided
What is zone merging in reference to tachy-arrhythmia therapy?
- means that if VF if detected and therapy is delivered, additional therapies in the VF zone for the same episode will not go to a lesser therapy
What is the term for when VF if detected and therapy is delivered, additional therapies in the VF zone for the same episode will not go to a lesser therapy
Zone merging
What is/are the criteria for VF episode termination following a CD?
- 8 to terminate
- need 8 consecutive V-V intervals greater than TDI
What is needed to abort a VF therapy delivery after detection?
4 V-V internals 60ms or greater than TDI
Which therapies are considered Non-committed shocks and what does that mean:
- VF RX=x1 and all cardioversions
- device synchronizes with the R-wave to prevent shocking on the T
What is needed to abort a cardio version shock?
- need 2 intervals 60ms or greater than the TDI to abort
-
What is the length of the confirmation window prior to shock/cardio version therapy delivery?
400ms
Which therapies are committed shocks?
- VF therapies 2-6
- device will try to synchronize but will deliver an asynchronous shock with no confirmation window
