Mintek Pacemaker LV-T ユーザーズマニュアル

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Stratos LV/LV-T Technical Manual  67 
2.1.3 DDI 
In contrast to DDD mode, the basic interval in the DDI mode is 
not restarted by sensed P-waves, but by ventricular sensed or 
paced events.  The VA delay is started together with the basic 
interval.  If atrial or ventricular sensing does not occur during the 
VA delay, the atrial pacing occurs at the end of the VA delay. 
Atrial pacing starts the AV delay.  If atrial sensing occurs outside 
of the atrial refractory period (ARP), a PMT safety interval or the 
FFP (far-field protection) window, atrial pacing is inhibited.  
However, the AV delay does not start with a sense event, but at 
the end of the VA interval.  Therefore, P-waves in the DDI mode 
do not trigger ventricular events. 
NOTE: 
For additional information on far-field protection window, see 
Section 2.3 “Timing Functions”. 
An atrial sensed event that occurs during the PMT protection 
window starts the atrial upper basic rate to avoid pacing during 
the vulnerable phase of the atrium.  If the interval of the atrial 
upper rate is longer than the basic interval, the AV delay is 
shortened by that same amount after atrial pacing, but only until 
the end of the safety interval. 
2.1.4 DVI 
The DVI mode is derived from the DDI mode.  In contrast to the 
latter, atrial sensing does occur.  Therefore, atrial pacing is 
delivered at the end of the AV delay.  Ventricular sensing within 
the AV delay inhibits atrial and ventricular pacing.  Ventricular 
sensing within the AV delay inhibits ventricular pacing. 
2.1.5 VDD 
The VDD mode corresponds to the DDD mode with the 
exception that it does not provide atrial pacing.  In the absence 
of a sense event, the basic interval starts with either an atrial 
sense event, a ventricular extrasystole or after expiration of the 
preceding basic interval.