sorin REPLY DR - Refractory Periods; Absolute Refractory Periods; Committed Period; Automatic AV Delay

20 – ENGLISH
The risk of pectoral stimulation is lower with bipolar pacing. With
bipolar sensing, the pacemaker is less sensitive to myopotentials and
to external electromagnetic noise.
Programming requirement: The pacemaker cannot be
programmed to bipolar configuration if a bipolar lead is not connected
(measurement of the impedance determines the type of lead present
at the time of bipolar configuration is programmed).
7.4. REFRACTORY PERIODS
Absolute refractory periods
Absolute atrial and ventricular refractory periods are initiated by any
sensed or paced ventricular or atrial event. These periods are composed
of a minimal Refractory Period and a triggerable Refractory Period. The
duration of the refractory periods lengthens automatically as needed.
PVAB special case: The Post Ventricular Atrial Blanking (PVAB) is an
absolute refractory period in which the minimal value is programmable.
Committed period
In dual-chamber pacing, atrial pacing may be sensed by the
ventricular sensing circuits, and may inhibit ventricular pacing. The
pacemaker is protected against this phenomenon (called Crosstalk)
by the committed period.
Automatic AV delay
The AV delay is the programmable time interval between atrial
sensing or pacing and ventricular pacing.
The rest AV delay is used at the programmed basic rate. The
exercise AV delay is used at the programmed maximum rate.
Between basic rate and maximum rate, the AV delay is calculated at
each cycle by the pacemaker on the basis of a linear relationship
between the AV delay and the atrial rate.