Mintek Pacemaker LV-T ユーザーズマニュアル

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Stratos LV/LV-T Technical Manual  89 
Reversion back to the programmed pacing mode occurs in a 
similarly programmable manner.  If a programmable number of 
atrial intervals (Z) out of 8 consecutive atrial intervals (p-p) are 
slower than the programmed mode switch intervention rate 
(Z out of 8), the device will revert back to the permanently 
programmed parameters.  Z is programmable from 3 to 8.  The 
device will also revert back to the permanent program if 2 
atrial-paced events occur or if no atrial paced or sensed events 
have occurred for at least 2 seconds. Each occurrence of mode 
switching resets the corresponding counter (X or Z) to a value of 
zero. 
Mode Switch Events are recorded in memory and are 
available to the user through the following diagnostics: 
• IEGM 
Recordings 
•  Tachy Episode Trends 
•  Mode Switch Trends 
•  Mode Switch Histogram 
•  Mode Switch Counter 
 
Mode Switching is temporarily suspended during magnet 
application and are inactive during ERI. 
2.9 PMT 
Management 
A PMT is defined as a tachycardia caused by inadvertently 
tracking the retrograde P-waves.  The PMT management feature 
includes PMT Protection/Termination and a programmable PMT 
detection and termination algorithm. 
2.9.1 Protection 
Pacemaker-mediated tachycardia (PMT) is normally triggered by 
ventricular depolarizations that are not synchronized with atrial 
depolarizations (e.g., VES).  The tachycardia is maintained in a 
retrograde direction by intrinsic VA conduction of the stimulated 
ventricular depolarization and in an antegrade direction by 
ventricular pacing of the pacemaker that is triggered by P-waves.  
It is the objective of the atrial PMT protection interval to not use 
retrogradely conducted atrial sensed events for pacemaker 
timing, but only to statistically evaluate them for detection of 
atrial tachycardia incidents.