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Stratos LV/LV-T Technical Manual  77 
In the case an atrial sense event falls within the PMT protection 
window, the Stratos CRT-Ps start a minimal ARP. 
2.3.6.2  Atrial Far-Field Protection 
In all dual chamber modes with atrial sensing, the 
Stratos CRT-Ps start an atrial FFP window upon each ventricular 
event to prevent sensing of far-field potentials in the ventricle.  
The atrial far-field protection window is separately programmable 
for ventricular sensed events at 30…(10)…100…(1)…200 ms 
and for ventricular paced events at 30…(10)…100 and 
100…(10)…220 ms.  If an atrial event occurs during the FFP 
window, the atrial event is classified as an invalid FFP event and 
has no influence on the timing of the CRT-P. 
With ventricular events (right ventricular sensed or paced, left 
ventricular paced, VES), the Stratos CRT-Ps start an FFP 
interval. 
2.3.7  Atrial PMT Protection 
In all atrial-controlled dual-chamber modes, Stratos CRT-Ps start 
the PMT protection interval after each ventricular stimulus.  This 
prevents retrograde conduction and triggering of 
pacemaker-mediated tachycardias (PMTs).  Right ventricular 
extrasystoles begin an extended PMT interval. 
In all dual-chamber modes controlled by the ventricle, the 
Stratos CRT-Ps start the PMT protection interval after each initial 
(right or left) ventricular event. 
The PMT protection interval after a Vp is freely programmable, 
while the PMT interval after VES is automatically set to 225 ms 
greater than the PMT interval after Vp (Nominal value: 250 ms/ 
AUTO (175…(5)…600 ms). 
If an atrial event occurs within the atrial PMT protection interval, 
the atrial event is classified such that the AV delay is not 
restarted. 
In the Stratos CRT-Ps, the PMT protection interval is started with 
a right or left ventricular paced event.