![Medtronic PROTECTA XT DR D314DRG Скачать руководство пользователя страница 268](http://html.mh-extra.com/html/medtronic/protecta-xt-dr-d314drg/protecta-xt-dr-d314drg_clinician-manual_1763148268.webp)
7.11.4 Evaluation of NCAP
When evaluating an ECG strip, you will notice that the AP-VP interval has been shortened
and the NCAP interval can be seen as the time between the AR and AP events (see
7.12 Interrupting pacemaker-mediated tachycardias
In tracking modes (DDDR and DDD), retrograde conduction can result in a
pacemaker-mediated tachycardia (PMT). A PMT is a repetitive sequence in which the
device responds to each retrograde P-wave by pacing the ventricle at an elevated rate,
which, in turn, generates a retrograde P-wave.
7.12.1 System solution: PMT Intervention
The PMT Intervention feature extends the PVARP after detecting a PMT. This interrupts the
PMT by causing the subsequent atrial-sensed event to fall within the refractory period.
7.12.2 Operation of PMT Intervention
PMT Intervention is available when the pacing mode is programmed to DDDR, DDD, or an
MVP mode (AAIR<=>DDDR or AAI<=>DDD). PMT Intervention functions when the device
is operating in the DDDR or DDD mode.
The device defines a PMT as 8 consecutive VP-AS intervals occurring at less than 400 ms.
When the device detects a PMT, the PMT Intervention feature forces a 400 ms PVARP after
the ninth paced ventricular event. This causes the next atrial sense to fall within the refractory
period. Because this refractory event is not tracked to the ventricle for 1 cycle, the PMT is
interrupted.
PMT Intervention is suspended for 90 s following the extended PVARP in order to prevent
unnecessary intervention in the presence of fast intrinsic atrial rates. The PMT detection
criteria can be met during normal elevated sinus rates, resulting in 1 dropped beat (not
tracked) every 90 s.
PVC Response can also prevent PMT. If the PVC Response and PMT Intervention features
are programmed to On and PMTs are observed, evaluate the atrial and ventricular lead
performance or positions, or consider drug therapy to reduce retrograde conduction.
Medtronic
PROTECTA™ XT DR D314DRG
268
Clinician Manual
Содержание PROTECTA XT DR D314DRG
Страница 2: ......
Страница 9: ...Index 488 Medtronic PROTECTA XT DR D314DRG Clinician Manual 9 ...
Страница 506: ......
Страница 507: ......