Discriminators Flashcards
What criteria must be present for PR Logic to deem an arrhythmia “AF” or “AFl”?
Ratio of sensed A/V events is >1:1, and v cycle rate is not regular (indicating AF) OR when AV pattern shows regular 2:1 or 3:2 conduction (indicating AFl).
What criteria must be present for PR Logic to deem an arrhythmia “Sinus Tach”?
1:1 AV ratio with a gradual Onset
What criteria must be present for PR Logic to deem an arrhythmia “Other 1:1 SVT’s”?
1:1 AV ratio when there are consistent, near-simultaneous depolarizations in both chambers (indicating an accelerated junctional rhythm or AV nodal re-entrant tachycardia.
What criteria must be present for PR Logic to deem an arrhythmia “Double Tachycardia”?
Rhythms are dissociated, indicating VT+SVT, VF+SVT, or FVT+SVT
What are PR Logic elements?
Rate, pattern, regularity, AV dissociation, AF evidence, and presence of far-field R-waves
How does PR Logic calculate rate?
Rate is calculated by looking at the median interval of the last 12 atrial events and the last 12 ventricular events. When the median of the last 12 ventricular events is longer than the programmed SVT limit, PR Logic will analyze the rate.
How does PR Logic use pattern when categorizing an arrhythmia?
Pattern examines the position and number of P waves relative to R waves and is used to examine A:V pattern information.
What discriminators are applied during sensing?
RV Lead Noise, Lead Integrity Alert, and TWOS
How does RV Lead Noise work?
Recognizes if lead noise is occurring by observing sensed events on the near-field signal, then checking the far-field signal to determine if there was an actual intrinsic event or not. If 3 out of 12 beats are classified as noise, the whole set of 12 will be classified as noise. If three out of the last twelve sets are classified as noise, detection will be withheld.
What feature is programmable within RV Lead Noise?
Timeout (15 sec - 2 min), nom 45 seconds
What clinical data is important to know about RV Lead Noise Timeout?
With a 45 sec timeout, device will correctly withhold therapy in 85% of lead failures.
How will you know if RV lead noise has been activated?
“VOS” under observation on QuickLook screen, also recorded in text of an episode.
What are the markers for RV lead noise?
N=noise and NT=noise discrimination time out
How does Lead Integrity Alert (LIA) work?
Needs 2/3 conditions to be met: sensing integrity counter >/= 30 for the last 3 days, at least 2 NSVT’s < 220 ms, and/or high lead impedance. Once condition is met an audible tone will sound from device and NID will increase to 30/40.
What factors does TWOS discriminator take into consideration when analyzing rhythms?
Amplitude, frequency content and pattern
Does the SVT limit apply to TWOS?
No
What discriminators are applied pre-counting?
Onset
What discriminators are applied at NID?
Wavelet, PR Logic, RVN and TWOS withhold therapy
What are the characteristics considered for PR Logic?
(FRRAPAFib) Far-field R waves, Rate, Regularity, AV dissociation, Pattern, and A Fib evidence