What are the 3 methods of VF induction?
Shock on T
What is shock on T?
1-2J shock on a T wave
What is Burst pacing induction of VF?
Pace at 300bpm
What is CD fibber?
Shock directly into myocardium
What are the detection RATE criteria that need to be met for an ICD to detect a nasty arrthymia?
Beats per minute i.e ranges
Classifies rhythm by detection zone
What are the detection DURATION criteria that need to be met for an ICD to detect a nasty arrthymia?
Number of intervals
Length of time in rhythm
What is consecutive rate duration criteria?
Number of simultaneous beats i.e 16 in a row
What is probabilistic detection duration?
Percentage or fraction i.e 12/16beats
What rhythm is consecutive criteria used for?
What rhythm is probabilistic criteria used for?
What do detection "zones" allow?
Allow discrimination between VT and VF based on cycle length
Fast VT (FVT) can also be set: What are the detection durations for FVT via VT and FVT via VF?
FVT via VT - Consecutive
FVT via VF - Probabilitic
Which therapy is best designed for VT?
Anti-Tachy Pacing (ATP)
Which therapy is best designed for FVT?
Which therapy is best designed for VF?
What is SVT discriminators used for?
Prevent detection of tachyarrhythmias caused by SVTs - preventing inappropriate therapy
What is waveform morphology?
ICD detects the normal waveform and uses it as a template for distinguishing normal and abnormal rhythms
How does an ICD use SVT Discriminators?
Wavelet threshold template
Onset (gradual/sudden - calculates average)
Dual chamber synchrony i.e. PR logic
What is ATP and what arrhythmias can it eliminate?
Pacing pulses delivered at higher rate in comparison to the detected rhythm
Terminate re-entry tachys (VT)
How does ATP work electrically? HOw does distance effect the efficiency?
ATP pulses bombard reentry circuit until the pulses refracts the circuit causing it to break
The further away the electrode is from the circuit means its less efficient
What are ATPs programmable:
: Number of times ATP will be applied upon re-detection
: Number of pulses per sequence
What is an ATP burst?
Series of pacing pulses delivered at equal intervals
Intervals decrement per sequence
What is an ATP ramp?
Series of pacing pulses delivered at ever decreasing intervals
Pulse added per sequence
What is burst+?
Burst therapy followed by 2 individually programmable pulses
What is Ramp+?
2 stimuli at individually programmable intervals, followed by a burst therapy
What is the shortest interval for ramp or burst?
Why is ATP always initiated first?
Done during charge
Which part of the QRS complex is the cardioversion shock delivered to?
What is a defibrillation shock?
Shock delivered to the heart to terminate a tachyarrhythmia
How does device see therapy success?
8 normal beats
Why is biphasic waveforms more appropriate for therapy?
Higher success rate
Reduced myocardial injury
Faster sinus rhythm restoration post shock