Specifications

7 x 9 inches (178 mm x 229 mm)
Medtronic Confidential
Refer to the “Reference man.” category in doc#163256 for Printing
Instructions.
196407001 Rev A
Rates
Overview
The following programmable rates control timing in Prodigy pacemakers:
■
Normal operating rates:
- Lower Rate
- Upper Tracking Rate
- Upper Activity Rate
■
Other operating rates:
- Hysteresis Rate (single chamber demand modes)
Additionally, rates calculated by the pacemaker are used for some
operations. These are:
■
sensor-indicated rate
■
mean atrial rate
The other operating rates are described in Chapter 14, along with the
functions that use them. The normal rates are described in this chapter.
A-A Timing
In all modes that pace the atrium, Prodigy pacemakers time from atrial
event to atrial event when possible (A-A timing). This timing method
mimics a natural sinus rhythm, producing A-A intervals that are nearly
equal, except when timing is interrupted by:
■
PACs in the DDIR and DDI modes,
■
PVCs in the DDDR, DDD, DDIR, and DDI modes, or
■
Ventricular sensed events during the VA interval in the DVIR and DVI
modes.
VA intervals vary due to adjustments by A-A timing operations designed to
achieve sensor-indicated or lower rate operation in the presence of varying
AV conduction.
12-2 Understanding Pacemaker Operations
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