Mintek Pacemaker LV-T ユーザーズマニュアル

90  Stratos LV/LV-T Technical Manual   

To prevent occurrence of a PMT, Stratos CRT-Ps start an atrial 
PMT protection interval after each ventricular paced event (right 
or left). If an atrial even is sensed within this PMT protection 
interval, this will neither start an AV delay nor a basic interval. 

The length of the PMT protection can be set to automatic (Auto).  
In this case, the PMT protection window can be automatically 
extended after the PMT is detected and terminated. 

The initial values of the PMT protection interval in the 
automatic setting at 175 ms after a Vp, and 400 ms after 
VES. 

 

It is the objective of PMT detection to identify ongoing PMTs, to 
distinguish them from the sinus rhythm and to terminate them.  
The detection of a PMT starts by measuring the Vp-As intervals.  
If these lie below the programmable PMT VA criterion 
(programming depends on the retrograde conduction time of the 
patient), the measurement of the stability of the Vp-As interval is 
started. 

The Stratos 

CRT-P’s PMT detection/termination algorithm 

consists of suspicion, confirmation and termination components 
and is described as follows. 

•  8 successive V pace-A sense (Vp-As) sequences have 

occurred with a length shorter than the VA criterion.  
This VA criterion is programmable between 250 and 500 
ms. 

•  The mean deviation of these 8 Vp-As intervals is less 

than the Stability criterion parameter, defined with 
respect to upper and lower values is ±25 ms.