Morphmatch Flashcards
Can Morphmatch be used in atrial based detection?
No ventricular detection only
Is morphmatch compatible with SMART
No - SMART must be off
What two algorithms must be satisfied before morphmatch kicks in
Onset and Stability
What is the purpose of Morphmatch
To distinguish SVT from VT
Is it available in HF CRT devices?
Yes - but only if LV sensing is off
Why must LV sensing be off for morphmatch to work
Because template is rolling - thus need constant intrinsic. Which reduces CRT pacing. Not like wavelet
Morphmatch is available in which zone
VT1 and VT2
3 ways it distinguishes morphology
Maximum Spike
Area
Vector
How many beats to build a template and what beats don’t count
32
Anything over 100bpm and ectopics
When is morphology reset
Daily // After reprogramming // Tachy Rx or periods of excessive variation
What is the morphology sampling rate
128hz (8ms)
What is the nominal SVT detection and can this be programmed
No programming - Double VT counter
If there is 1 unstable beat - how much does morphmatch drop the detection counter?
By 20 - old devices used to start over again
Morphmatch limitations
Only for initial detection
Rate dependent BBB will throw it
Paced rhythm - can’t initialised
Cant be used with SMART
What are the 3 thresholds for morphmatch and their values
Low = 28 (More sensitive)
Std = 36
High = 42 (More specific)
Morph counter must be below what % of VT counter to be classified as SVT
50%
