User's Manual

Timing Functions

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Note: It is recommended that the lowest possible values

be selected, so that ventricular/atrial sensing is

ensured for the period during which

ventricular/atrial intrinsic rhythm may occur.

Note: It is also recommended that the selected values be

high enough to prevent undesired sensing of

pacing in the other chamber.

This is possible with high atrial/ventricular pulse

energies and/or high ventricular/atrial sensitivities.

The blanking period is automatically extended by one increment in

some combinations of pacing and sensing polarities in order to prevent

crosstalk. The programmer will indicate the amount by which the

blanking period has been extended.

Safety AV Delay

In the DDD(R), DDT(R)/A, DDT(R)/V, DDI(R) and DVI(R) pacing modes,

the safety AV delay is started with atrial pacing. If a ventricular sense

event occurs within the safety AV delay, the pacemaker paces in the

ventricle at the end of the interval (Vsp = ventricular safety pace). If the

AV delay is shorter than the safety AV delay, pacing occurs at the end

of the AV delay.

This prevents ventricular pulse inhibition due to ventricular sensing of

atrial pacing (which would be crosstalk). (See Figure 10).