Timing Cycles Flashcards
What is the low rate?
The lowest rate the pacemaker will allow.
What is ventricular blanking?
A non-programmable blanking period on the ventricular channel initiated by a ventricular event. Prevents the device from oversensing the ventricular event that initiates this timer.
What is the ventricular refractory period?
A programmable, but rarely changed, interval on the ventricular channel, following a ventricular event where events are seen, but do not restart the AV interval/low rate timer. Designed to prevent T wave oversensing.
What is atrial blanking?
A non-programmable blanking period on the atrial channel that prevents oversensing of the atrial pacing spike and/or far-field oversensing.
What is the atrial refractory period/post ventricular atrial refractory period?
A timer initiated on the atrial channel by a ventricular event that prevents tracking of retrograde P waves/PMT. Atrial events in this period still count towards arrhythmia detection, but do not restart timers.
What is post atrial ventricular blanking?
A timer initiated by an atrial pace on the ventricular channel that prevents the oversensing of the atrial pacing spike/crosstalk.
What is crosstalk inhibition?
Inappropriate sensing on the ventricular channel caused by a pace atrial event and can cause a dropped ventricular beat.
What is ventricular safety pacing?
Provides an extra window that starts after every Ap event. Any ventricular event sensed in this window will cause a ventricular safety pace at a 110ms AV delay.
What can you do to manage crosstalk?
Decrease atrial output, if possible, decrease ventricular sensitivity (less sensitive), ensure lead is programmed bipolar, if possible, increase PVAB. Ensure the device is not undersensing the atrium - most common cause of crosstalk.
What is post ventricular atrial blanking?
Prevents ventricular events from being sensed on the atrial channel/far-field oversensing. Initiated on the atrial channel by a ventricular event, usually 130-150ms.
What are the common causes of a loss of AV synchrony?
PVC, LOC in atrium, atrial over/undersensing
What is A-A timing?
A-A interval remains constant regardless of where Vs occurs in timing. Intervals (AV/VA intervals) will adjust to compensate.
What is V-V timing?
VA interval does not change; A-A interval may shorten
What is modified A-A timing?
A-A timing, except in the case of a PVC, where a PVC will reset the VA interval, in hopes of preventing.
What is TAB?
Total atrial blanking
